Radio Propagation Measurements and Statistical Channel Models for Outdoor Urban Microcells in Open Squares and Streets at 142, 73, and 28 GHz

IEEE Microwave Magazine

A new multiuser terahertz (THz) measurement facility, or “ THz Lab ,” located at the New York University (NYU) wireless research center, develops a next-generation laboratory to enable pioneering research at the upper reaches of the radio spectrum: the sub-THz (100–300 GHz) and THz (0.3–3 THz) frequency bands. The cellular telephone industry’s recent realization of the viability of the millimeter wave (mm-wave) radio spectrum for 5G has created a need for the next-generation measurement platform that can promote foundational research for wireless communications, circuit design, antennas and propagation, and novel materials into the 6G era and beyond . The THz Lab , funded by a US$3 million National Science Foundation (NSF): Major Research Instrumentation (MRI) grant, explores the spectrum frontier at frequencies from the mm-wave and into the THz bands, where material and propagation …

IEEE Microwave Magazine

A new multiuser terahertz (THz) measurement facility, or “ THz Lab ,” located at the New York University (NYU) wireless research center, develops a next-generation laboratory to enable pioneering research at the upper reaches of the radio spectrum: the sub-THz (100–300 GHz) and THz (0.3–3 THz) frequency bands. The cellular telephone industry’s recent realization of the viability of the millimeter wave (mm-wave) radio spectrum for 5G has created a need for the next-generation measurement platform that can promote foundational research for wireless communications, circuit design, antennas and propagation, and novel materials into the 6G era and beyond . The THz Lab , funded by a US$3 million National Science Foundation (NSF): Major Research Instrumentation (MRI) grant, explores the spectrum frontier at frequencies from the mm-wave and into the THz bands, where material and propagation …

Now reissued by Cambridge University Press, the updated second edition of this definitive textbook provides an unrivaled introduction to the theoretical and practical fundamentals of wireless communications. Key technical concepts are developed from first principles, and demonstrated to students using over 50 carefully curated worked examples. Over 200 end-of-chapter problems, based on real-world industry scenarios, help cement student understanding. The book provides a thorough coverage of foundational wireless technologies, including wireless local area networks (WLAN), 3G systems, and Bluetooth along with refreshed summaries of recent cellular standards leading to 4G and 5G, insights into the new areas of mobile satellite communications and fixed wireless access, and extra homework problems. Supported online by a solutions manual and lecture slides for instructors, this is the ideal foundation for senior undergraduate and graduate courses in wireless communications.

Exemplary apparatus can be provided that can comprise a plurality of antennas; a plurality of conversion systems, each capable of accepting and/or producing one or more digital signals; a circuit (eg, radio circuit) configured to couple the antennas to the conversion systems; and computer arrangement configurable to selectively control operation of the conversion systems according to one or more predetermined criteria. In some embodiments, the conversion systems can be configured to utilize different sampling rates and/or quantization resolutions and/or to accept and/or produce different numbers of digital signals. Exemplary conversion systems can be enabled/disabled such that one or more can operate simultaneously based on, eg, subframe timing of received signal, predetermined schedule, power or energy of received signals, availability of reference signals, channel coherence time, and apparatus energy …

Wireless devices, and particularly mobile devices such as cellphones, PDAs, computers, navigation devices, etc., as well as other devices which transmit or receive data or other signals at multiple frequency bands utilize at least one antenna to transmit and receive and a plurality of different bands (eg, GSM cellular communication band; Bluetooth short range communication band; ultrawideband (UWB) communications, etc.). These wireless devices can simultaneously transmit or receive at a plurality of different bands, or simultaneously transmit and receive at different bands. The wireless devices have the ability to use a single physical structure (eg, an antenna for transmission and reception of many different bands. The antenna can he either actively tuned or passively tuned using one or more elements. The antenna may comprise a plurality of antenna elements or antennas, and at least one antenna may be a …

With the advancement of wireless communication to sub-terahertz (THz) and millimeter-wave (mmWave) bands, accurate channel models and simulation tools are becoming increasingly important for modeling a wide range of frequencies and scenarios. This paper provides a comprehensive tutorial on generating drop-based and spatial consistency-based channels using the open-source MATLAB-based NYU Channel Model Simulator (NYUSIM). NYUSIM is built on extensive real-world radio propagation measurements for the frequency range of 0.5-150 GHz, covering a variety of scenarios such as Urban Microcell (UMi), Urban Macrocell (UMa), Rural Macrocell (RMa), Indoor Hotspot (InH), and Indoor Factory (InF). Additionally, an overview of the evolution of simulators used to design and analyze wireless systems since the early days of cellular communication is also provided. We introduce the most popular …

Ray tracing is a powerful tool that can be used to predict wireless channel characteristics, reducing the need for extensive channel measurements for channel characterization, evaluation of performance of sensing applications such as position location, and wireless network deployment. In this work, NYURay, a 3D mmWave and sub-THz ray tracer, is introduced, which is calibrated to wireless channel propagation measurements conducted at 28, 73, and 140 GHz, in indoor office, outdoor, and factory environments. We present an accurate yet low-complexity calibration procedure to obtain electrical properties of materials in any environment by modeling the reflection coefficient of building materials to be independent of the angle of incidence, a simplification shown to be quite effective in [1] over 30 years ago. We show that after calibration, NYURay can accurately predict individual directional multipath signal power …

In this paper, we expand upon a new metric called the Waste Factor , a mathematical framework used to evaluate power efficiency in cascaded communication systems, by accounting for power wasted in individual components along a cascade. We show that the derivation of the Waste Factor, a unifying metric for defining wasted power along the signal path of any cascade, is similar to the mathematical approach used by H. Friis in 1944 to develop the Noise Factor , which has since served as a unifying metric for quantifying additive noise power in a cascade. Furthermore, the mathematical formulation of can be utilized in artificial intelligence (AI) and machine learning (ML) design and control for enhanced power efficiency. We consider the power usage effectiveness (PUE), which is a widely used energy efficiency metric for data centers, to evaluate for the data center as a whole. The use of allows …

In this paper, we expand upon a new metric called the Waste Factor , a mathematical framework used to evaluate power efficiency in cascaded communication systems, by accounting for power wasted in individual components along a cascade. We show that the derivation of the Waste Factor, a unifying metric for defining wasted power along the signal path of any cascade, is similar to the mathematical approach used by H. Friis in 1944 to develop the Noise Factor , which has since served as a unifying metric for quantifying additive noise power in a cascade. Furthermore, the mathematical formulation of can be utilized in artificial intelligence (AI) and machine learning (ML) design and control for enhanced power efficiency. We consider the power usage effectiveness (PUE), which is a widely used energy efficiency metric for data centers, to evaluate for the data center as a whole. The use of allows …

IEEE Transactions on Wireless Communications

This paper presents sub-Terahertz (THz) channel characterization and modeling for an indoor industrial scenario based on radio propagation measurements at 142 GHz in four factories. We selected 82 transmitter-receiver (TX-RX) locations in both line-of-sight (LOS) and non-LOS (NLOS) conditions and collected over 75,000 spatial and temporal channel impulse responses. The TX-RX distance ranged from 5 to 87 m. Steerable directional horn antennas were employed at both ends and were switched between vertical and horizontal polarization. Measurements were conducted with the low RX and high RX to characterize the propagation channel for close-to-floor applications such as automated guided vehicles. Results show that the low RXs experience an average path loss increase of 10.7 dB and 6.0 dB at LOS and NLOS locations, respectively. In addition, channel enhancement measurements were conducted …

This paper presents sub-Terahertz (THz) radio propagation measurements at 142 GHz conducted in four factories with various layouts and facilities to explore sub-THz wireless channels for smart factories in 6G and beyond. Here we study spatial and temporal channel responses at 82 transmitter-receiver (TX-RX) locations across four factories in the New York City area and over distances from 5 m to 85 m in both line-of-sight (LOS) and non-LOS (NLOS) environments. The measurements were performed with a sliding-correlation-based channel sounder with 1 GHz RF bandwidth with steerable directional horn antennas with 27 dBi gain and 8° half-power beamwidth at both TX and RX, using both vertical and horizontal antenna polarizations, yielding over 75,000 directional power delay profiles. Channel measurements of two RX heights at 1.5 m (high) emulating handheld devices and at 0.5 m (low) emulating …

IEEE Communications Magazine

Until the birth of wireless at the end of the 19th century, the world had never known real-time ubiquitous communications. Printed newspapers of the day contained information that was often days, if not weeks, old with little hope of widespread verification of reported events. Part 1 of this series [1] gave an overview of the fascinating hobby of ham radio, and showed how the grass roots effort of hobbyists and the sinking of the Titanic opened up the airwaves for the world's first amateur radio operators. Now, in Part 2, we see how amateur radio was at the forefront of the wireless revolution that brought AM and FM radio broadcasting, television, and mobile communications to the world. As shown here, it was the ingenuity and tenacity of hams that brought forth the information age in all of its forms.

arXiv preprint arXiv:2312.15987

The next generation of wireless communication, is expected to harness the potential of the sub-THz bands to achieve exceptional performance and ubiquitous connectivity. However, network simulators such as ns-3 currently lack support for channel models above 100 GHz. This limits the ability of researchers to study, design, and evaluate systems operating above 100 GHz. Here, we show that drop based NYUSIM channel model can be used to simulate channels above 100 GHz in all 3GPP scenarios including urban microcell (UMi), urban macrocell (UMa), rural macrocell (RMa), indoor hotspot (InH), and indoor factory (InF). We evaluate the full stack downlink end-to-end performance (throughput, latency and packet drop) experienced by single user equipment (UE) connected to a Next Generation Node B (gNB) operating in the sub-THz bands for three gNB-UE antenna configurations: 8x8-4x4, 16x16-4x4, and 64x64-8x8 by using NYUSIM channel model at 140 GHz in the ns-3 mmWave module. Additionally, it is found that determining the exact number of realizations required to obtain statistically significant results using simulation platforms like ns-3 remains challenging, as end-to-end performance metrics vary strongly with the number of realizations. Hence, we show the variation in throughput vs number of realizations and find the optimal number of realizations required to obtain statistically significant results. We strongly encourage researchers worldwide to adopt a similar approach, as it enables the readers to assess the accuracy and reliability of the reported results and enhance the finding's overall interpretability.

An ultrawideband radio transceiver/repeater provides a low cost infrastructure solution that merges wireless and wired network devices while providing connection to the plant, flexible repeater capabilities, network security, traffic monitoring and provisioning, and traffic flow control for wired and wireless connectivity of devices or networks. The ultrawideband radio transceiver/repeater can be implemented in discrete, integrated, distributed or embedded forms.

This paper presents sub-Terahertz (THz) radio propagation measurements at 142 GHz conducted in four factories with various layouts and facilities to explore sub-THz wireless channels for smart factories in 6G and beyond. Here we study spatial and temporal channel responses at 82 transmitter-receiver (TX-RX) locations across four factories in the New York City area and over distances from 5 m to 85 m in both line-of-sight (LOS) and non-LOS (NLOS) environments. The measurements were performed with a sliding-correlation-based channel sounder with 1 GHz RF bandwidth with steerable directional horn antennas with 27 dBi gain and 8° half-power beamwidth at both TX and RX, using both vertical and horizontal antenna polarizations, yielding over 75,000 directional power delay profiles. Channel measurements of two RX heights at 1.5 m (high) emulating handheld devices and at 0.5 m (low) emulating …

Exemplary system, method, and computer-accessible medium for protecting at least one integrated circuit (IC) design, includes generating an abstract syntax tree (“AST”) based on a hardware description language and a first register-transfer level (RTL) design. The method also includes selecting semantic elements in the AST to lock and locking the selected semantic elements. Additionally, the method includes a procedure for generating a second RTL design.

IEEE Transactions on Antennas and Propagation

This paper presents a compact AMC structure used as a shielding element for a generic wearable RFID tag at UHF frequencies for on-body applications, with an overall footprint limited to an area of only 0.03 λ 0 2 (41.4 mm × 82.8 mm). Thanks to the isolation provided by the AMC planar structure, the tag antenna gain and reading range are increased of about one order of magnitude in comparison with the case of a conventional tag attached to the human body. The designed antenna is platform tolerant, with a very good robustness and isolation with respect to the human body, exhibiting a high reliability. The AMC structure is implemented on a thin, flexible and biocompatible high permittivity silicon-doped dielectric substrate, with apertures both in the substrate and in the ground plane to allow skin transpiration. Therefore, the presented device can be effectively used also as an epidermal antenna, allowing the “on …

IEEE Transactions on Antennas and Propagation

Authors of this paper have recently formulated a maximum bound of super-directivity of self-resonant antennas for a given minimum Q (maximum frequency bandwidth). This paper complements the above work treating the influence of the losses. The problem is faced by assuming small losses in terms of surface resistance over the metalized surface of the minimum sphere circumscribing the antenna. The final closed form formula shows that the maximum gain is obtained by a summation that resembles the well-known Harrington’s sum for maximum directivity, except that the expansion coefficients are weighted by the radiation efficiency of each spherical harmonic. The formulation is next generalized to the case of self-resonant antenna, providing a tighter bound for any losses. For small antennas, we provide a simple interpretation of the field corresponding to the maximum gain in terms of dipolar and quadrupolar …

IEEE Transactions on Antennas and Propagation

This work proposes a Smart Electromagnetic Skin (SES) to enhance mm-wave 5G communications in indoor scenarios. The SES is based on a passive panel of reflective elements that not only redirects the impinging wave provided by the base station but also shapes the reflected field into a desired direction. The SES aims to overcome a blind zone in a coverage generated by the different propagation issues at those frequencies. The design of the SES is based on the well-known technique of the Intersection Approach for near field shaping. This fact is particularly important since the coverage in this type of scenario would have the users within the Fresnel Region of the SES and not in far-field conditions. The design goal is to generate a prescribed shaped beam in a near field area, operating in two orthogonal linear polarizations. Then, the results obtained with the synthesis techniques are used to design a …

IEEE Transactions on Antennas and Propagation

A novel trimode broadband high-gain dipole with mode compression is proposed in this communication: first, by introducing bend stubs to realize the modification of the forward and reverse currents of the fifth- and seventh-order modes, to improve the gain; second, by introducing straight stubs to extend the current path of the seventh-order mode, to shift the seventh-order mode left, and to combine with the fifth-order mode; and finally, by introducing parasitic dipoles to further modify the currents and to generate the coupled resonance modes, to enhance the gain and the bandwidth again. Characteristic mode analysis is utilized, and a prototype is fabricated to verify the principle experimentally. The measurement shows that the antenna worked in the 3.25–4.05-GHz band (25.5%) and a high gain of 7.9 ± 0.6 dBi in the desired n-78 (3.3–3.8 GHz) band.

IEEE Transactions on Antennas and Propagation

Antenna array failures have been investigated since the early 1990’s, often making use of array factor (AF) theory to accelerate the analysis. However, AF modeling is not always appropriate for reflectarray (RA) antennas due to their operation in a scattering mode rather than being a driven antenna. Therefore, full-wave analysis is required to model RAs with failures. Unfortunately, this places a tremendous computational burden on any attempt at reoptimizing the RA to heal its performance. To overcome this issue, we introduce here an efficient method which exploits adjoint optimization to make RA healing tractable. To demonstrate the approach, a 25 x 25 element RA is analyzed under multiple failure scenarios to determine the expected gain recovery after optimization. The proposed optimization framework achieves a 550x speed improvement over conventional approaches thus making optimization-based RA …

IEEE Transactions on Antennas and Propagation

Happy New Year! I am delighted to be writing this editorial to present the January 2024 issue of the IEEE transactions on Antennas and Propagation (TAP). More than one year has passed since I took over as the journal’s Editor-in-Chief and time has come to look back at the previous year and reflect on the journal’s position and the actions taken toward further elevating its status . I am pleased to report that throughout 2023, TAP has maintained and strengthened its role as the flagship journal in the vibrant field of antennas and propagation, by remaining committed to the publication of timely and rigorous research.

IEEE Transactions on Antennas and Propagation

In this paper, we design and verify a mmWave reverberation chamber operating in the 24-140 GHz band. The chamber is designed to facilitate over-the-air measurements of next-generation integrated antennas operating at high frequencies. For such systems, it is important to perform fast and accurate measurements of the radiated or received power over a wide frequency range. The reproducibility of our proposed chamber configuration is on average over the frequency band better than 0.2 dB when using the minimum advised number of mode-stirring samples. The chamber loss does not exceed 42 dB, and the chamber-decay time remains approximately 0.3 μs across the frequency range, indicating that the chamber would likely remain operational above 140 GHz. As an example of the performance of the chamber, we show that antenna-efficiency measurements can be performed within only a few percent …

IEEE Transactions on Antennas and Propagation

Reconfigurable intelligent surfaces (RISs) are electromagnetically passive controllable structures, deflecting incident wave beams in tunable directions. A usual way to design RIS using metasurfaces (MSs) is based on the approximation in which the reflective properties of a uniform MS are attributed to unit cells of the non-uniform one. We call this approximation the reflection locality (RL) and analyze its applicability. We prove that RL holds for a wide range of incidence and deflection angles if and only if uniform MSs based on which the non-uniform one is generated possess so-called angular stability (AS). AS of an infinite uniform MS (that we call generic MS) means that its reflection coefficient is independent on the incidence angle for both TE and TM polarizations.

IEEE Transactions on Antennas and Propagation

This article proposes a novel prediction method for efficient inverse modeling of a compact wireless power transfer (WPT) system. Impedance matching circuit analysis with admittance (J-) inverter theory is used for coupling analysis. Then, a simple translator-inspired neural network is proposed to predict scattering (S-) parameters from 100 MHz to 1 GHz for each coupling case. The training dataset comprises 2900 randomly generated dimensions and the corresponding S-parameters via full-wave simulation. Consequently, the power transfer efficiency (PTE) can be figured out using the S-parameter, which varies from different coupled modes. Then, a dual-annealing algorithm is leveraged to find the best dimensions. The predicted dimensions, including the transmitter (Tx) and receiver (Rx) layouts, values of the etched capacitors, and WPT distances, meet the design purposes. Compared to the state-of-the-art …

IEEE Transactions on Antennas and Propagation

A comprehensive understanding of outdoor urban radio propagation at mmWave and sub-THz frequencies is crucial for enabling novel applications such as wireless cognition, precise position-location, and sensing. This paper summarizes extensive measurements and statistical analysis of outdoor radio propagation data collected in New York City between 2012 and 2021 to formulate a multi-band empirical 3-D statistical channel model (SCM) for outdoor urban open squares and streets. Path loss models and SCMs are derived from over 21000 power delay profiles (PDP) measured in Brooklyn and Manhattan. Analysis of multipath components in PDPs reveal underlying statistical distributions for wireless channel parameters, including number of time-clusters (TC), subpaths in TCs, delays and powers of TCs and subpaths, and spatial-cluster directions. Observations at 142 GHz suggest a sparse channel as …

IEEE Transactions on Antennas and Propagation

While Luneburg lenses are among the best multi-beam antenna topologies if one seeks low scan losses and large bandwidths, they also require very specific refractive indices and therefore limit a designer’s degrees of freedom when realizing such a lens. The purpose of this paper is to find a generalized expression for the optimal refractive index distribution, by loosening the hypothesis that the value at the lens edge be equal to that of the external medium. By addressing the problem with different methods offering different levels of complexity, we propose a simple empirical expression linking the refractive index at the lens center and at the lens edge. The existence of Whispering Gallery Modes (WGMs), as the lens edge is no longer matched with the external medium, causes the generalized lenses to behave poorly at specific frequencies. We eventually show that this effect can be mitigated following appropriate …

IEEE Transactions on Antennas and Propagation

In this work, a wideband and high-selectivity amplifying frequency selective surface (AFSS) has been proposed. To achieve a wideband FSS, meta-vias that are employed to couple energy between a microstrip line and slot lines have been created. A transmission zero has been introduced at high frequency by short-circuiting microstrip lines in parallel, which improves the selectivity of FSS and decreases the out-of-band level. To achieve passband amplification, the amplifier is integrated into the microstrip line. Compared to the other FSS available, AFSS can increase the amplitude of electromagnetic waves. This makes AFSS potentially helpful in future communication systems, such as improving signal-to-noise ratio, antenna gain, signal detection, and signal isolation. To better understand the working mechanism of the AFSS, its equivalent circuit has been proposed. The amplifying passband of the AFSS ranges …

IEEE Transactions on Antennas and Propagation

In this paper we present an efficient implementation of the spectral domain Method of Moments (SD-MoM) for the analysis of periodic multilayered structures in the case where asymmetric rooftop basis functions defined in a non–uniform mesh are used. This mesh only needs to be generated in the bounding rectangle that encloses the electric or magnetic current to be discretized. The slowly convergent double infinite summations involved in the MoM matrix entries are computed by means of four two–dimensional Non–Uniform Fast Fourier Transforms (NUFFT-2D), and the singularities and quasi-singularities appearing in the spectral functions that are subjected to the NUFFT-2D are skipped by rearranging terms and introducing eight additional one-dimensional NUFFTs (NUFFT-1D). The code implementing the NUFFT-accelerated SD-MoM approach has been used to analyze cells of frequency selective surfaces …

IEEE Transactions on Antennas and Propagation

Reconfigurable intelligent surfaces (RISs) are electromagnetically passive controllable structures, deflecting incident wave beams in tunable directions. A usual way to design RIS using metasurfaces (MSs) is based on the approximation in which the reflective properties of a uniform MS are attributed to unit cells of the non-uniform one. We call this approximation the reflection locality (RL) and analyze its applicability. We prove that RL holds for a wide range of incidence and deflection angles if and only if uniform MSs based on which the non-uniform one is generated possess so-called angular stability (AS). AS of an infinite uniform MS (that we call generic MS) means that its reflection coefficient is independent on the incidence angle for both TE and TM polarizations.

IEEE Transactions on Antennas and Propagation

An all-metal evanescent wave filtenna (EWF), which operates below the cutoff frequency of the rectangular waveguide (RWG), and exhibits a small frequency ratio (FR) of 1.06 between the radiation null (RN) and transmission pole (TP) is developed in this communication. By partially filling a capacitive metasurface (CMS) with two slits in the cross section of RWG, the transverse and vertical electric resonant modes in the cross section can be generated at different frequencies. For the former, it is orthogonal to the TE10 mode of the RWG, and can introduce the RN due to the mode-mismatch. For the latter, the TP can be obtained due to the evanescent wave (EW) coupling principle. Several key parameters of the CMS are studied based on the mode analysis to illustrate the independent controllability of the RN, TP, and resultant FR. By properly adjusting the design parameters of CMSs, a diplex EWF working in S-band …

IEEE Transactions on Antennas and Propagation

For near-field (NF) antenna measurements where the phase cannot be measured at all or with sufficient accuracy, it is necessary or it may be preferable to use phaseless measurements. Of the four main categories of phaseless measurement techniques, the well-known two-scan technique with two concentric measurement spheres is investigated systematically. Probe correction is included as an integral step of the phase retrieval. The method is validated numerically and experimentally using measured data of a large 12-GHz reflector antenna. Performance is examined with respect to the separation between measurement spheres, radius of the measurement sphere, and initial guess. It is demonstrated that the two-scan technique can perform very well for both co-and cross-polar radiation patterns of very high complexity using probe-corrected spherical NF antenna measurements with a dual-ported probe and on …

IEEE Transactions on Antennas and Propagation

This communication presents a quad-polarization reconfigurable multifaceted conformal array of wide coverage range and high gain that is suitable for unmanned aerial vehicle (UAV) communication applications. The design features a sparse array layout comprised of three conformal subarrays, where each subarray includes nine quad-polarization reconfigurable radiating elements. The radiating element is a single-port excited patch radiator loaded by edge slots for size miniaturization and central shorting pin for biasing simplification, which is integrated with a low-complicity reconfigurable feeding network consisting of relatively few PIN-diodes and biasing lines. Using such a miniaturized and high-efficiency element, a polarization reconfigurable conformal array prototype is designed, fabricated, and experimentally characterized. Simulation and measurement results have shown that the presented conformal …

IEEE Transactions on Antennas and Propagation

A new wideband differentially fed dual-polarized antenna with stable radiation pattern for base stations is proposed and studied. A cross-shaped feeding structure is specially designed to fit the differentially fed scheme and four parasitic loop elements are employed to achieve a wide impedance bandwidth. A stable antenna gain and a stable radiation pattern are realized by using a rectangular cavity-shaped reflector instead of a planar one. A detailed parametric study was performed to optimize the antenna's performances. After that, a prototype was fabricated and tested. Measured results show that the antenna achieves a wide impedance bandwidth of 52% with differential standing-wave ratio <;1.5 from 1.7 to 2.9 GHz and a high differential port-to-port isolation of better than 26.3 dB within the operating frequency bandwidth. A stable antenna gain ( dBi) and a stable radiation pattern with 3-dB beamwidth of 65° …

IEEE Transactions on Antennas and Propagation

The ability to utilize resources to meet the need of growing diversity of communication services and user behavior marks the future of cognitive wireless communication systems. Cognitive wireless technologies for vehicular communications, in combination with Orbital Angular Momentum (OAM) modes aim at extending Non-Line-Of-Sight (NLOS) short-distance communications for smart mobility. In this regard, OAM antenna frameworks need to be developed to support these technologies. In this work, we describe a magnetoelectric dipole antenna framework supporting OAM modes. The framework is derived from moment tensors of specific vector spherical harmonic functions synthesized from dipoles. The antenna framework is discussed in terms of OAM generation, and it is validated numerically and experimentally for l = 1 OAM mode, achieving more than 500MHz operation bandwidth at the frequency of …

IEEE Transactions on Antennas and Propagation

In this paper, broadband dual-circularly-polarized (dual-CP) antenna arrays with independent control of polarizations are proposed and demonstrated at K -band. By introducing folded Γ-shaped end loadings and corner truncation, a dual-CP magneto-electric dipole (ME-dipole) element with a compact footprint and a broad bandwidth of 22.5% is realized. Based on such element, a 2 × 2-element sequential rotation subarray is constructed. By employing a high dielectric constant substrate, a stacked array feeding configuration is devised by placing two sets of microstrip feeding circuits above and below the ground plane for independent dual-CP beamforming. Importantly, the feeding circuitry is fully confined within the area of the array elements without occupying any extra space. Furthermore, a 4 × 4-element array is synthesized for obtaining dual-CP radiated beams over a broad bandwidth with improved CP purity …