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This paper presents a single-chip bits-to-antenna transmitter (TX) for >100 Gbps in 45nm CMOS SOI. The construction of the 64QAM constellation is achieved directly in the RF domain by utilizing three QPSK sub-TXs with weighted amplitude. This method significantly reduces the need to address power amplifier nonlinear effects in high-order modulation, thereby creating room for TX enhancements in both bandwidth and output power. To further improve TX performance, multi-step phase alignment strategies, and a local oscillator leakage suppression technique have been incorporated. With 40-GHz RF bandwidth, the RF-64QAM TX prototype is able to achieve a measured data rate of 120 Gbps with 15dBm effective isotropic radiated power (EIRP).

In mm-wave MIMO systems, hybrid precoder and combiner designs enhance antenna gain for improved transmission efficiency. However, beam-squint conditions during transmission impact throughput, affecting codebook and increasing beam focus and angle of arrival difference, degrading channel performance. Hence, a novel the Pylon ∂ PSO Method has been proposed to minimize codebook size and array gain, reducing the difference between beam focus and angle of arrival. A Grassmannian codebook is created without compromising throughput. For channel state estimation, existing techniques using the Kronecker product which face convergence errors due to improper hyperparameter matrix selection. Hence, an innovative Lagrange Dual technique and Separable K-Singular Value DE polymerization (K-SVDEp) have been used in dictionary learning that results in the Pt3 product to find the best dictionaries in which block sparse values are estimated using a Deep Ridge Regression Neural Network-based estimator that gives an optimum hyperparameter matrix and eliminates convergence error. Furthermore, designing a combiner from the hyperparameter matrix faces mathematical challenges. Hence, a novel Glasgow technique is utilized which converges the design parameter value with a local optimum obtained using the GEO algorithm. The proposed design has been implemented on the MATLAB platform and outperforms existing techniques with a high spectral efficiency of 45 bits/Hz, SNR of 13.4 dB, and low SER of 1 0 - 4 . [ABSTRACT FROM AUTHOR]

Summary: This article analyses a substrate integrated waveguide (SIW) fractal koch surface (FKS) slot antenna performance for Ka‐band applications. This FKS slot shape is obtained by modifying the conventional rectangular slot with the first iteration of the FKS method. The resultant FKS slot behaves as a radiator in the provided space. A single‐ and two‐element FKS slotted SIW antenna characteristics are analysed on a 20 mil thick RT/Duroid 5880 substrate and compared with the conventional rectangular slot. The proposed antenna with dimensions 15×5×0.508 mm3 achieves an impedance bandwidth from 27.4 to 32.1 GHz with a fractional bandwidth of 15.79% and achieves a gain of 8.3 dBi in broadside direction by improving space filling factor in SIW structure. The prototype of the SIW‐fed FKS slotted antenna array measurement results is satisfactory with the simulation results. [ABSTRACT FROM AUTHOR]

In this paper, we present the design of a millimeter-wave 1 × 4 linear MIMO array antenna that operates across multiple resonance frequency bands: 26.28–27.36 GHz, 27.94–28.62 GHz, 32.33–33.08 GHz, and 37.59–39.47 GHz, for mm-wave wearable biomedical telemetry application. The antenna is printed on a flexible substrate with dimensions of 11.0 × 44.0 mm2. Each MIMO antenna element features a modified slot-loaded triangular patch, incorporating 'cross'-shaped slots in the ground plane to improve impedance matching. The MIMO antenna demonstrates peak gains of 6.12, 8.06, 5.58, and 8.58 dBi at the four resonance frequencies, along with a total radiation efficiency exceeding 75%. The proposed antenna demonstrates excellent diversity metrics, with an ECC < 0.02, DG > 9.97 dB, and CCL below 0.31 bits/sec/Hz, indicating high performance for mm-wave applications. To verify its properties under flexible conditions, a bending analysis was conducted, showing stable S-parameter results with deformation radii of 40 mm (Rx) and 25 mm (Ry). SAR values for the MIMO antenna are calculated at 28.0/38.0 GHz. The average SAR values for 1 gm/10 gm of tissues at 28.0 GHz are found to be 0.0125/0.0079 W/Kg, whereas, at 38.0 GHz, average SAR values are 0.0189/0.0094 W/Kg, respectively. Additionally, to demonstrate the telemetry range of biomedical applications, a link budget analysis at both 28.0 GHz and 38.0 GHz frequencies indicated strong signal strength of 33.69 dB up to 70 m. The fabricated linear MIMO antenna effectively covers the mm-wave 5G spectrum and is suitable for wearable and biomedical applications due to its flexible characteristics. [ABSTRACT FROM AUTHOR]

This article presents a meticulously engineered MIMO antenna system tailored specifically for 26 GHz millimeter-wave applications. It integrates a compact planar-patterned metamaterial (MTM) structure, carefully designed with split square and hexagonal unit cells to realize an effective near-zero index (NZI) range for both permeability and permittivity. Comprehensive wave propagation analysis along the y-axis rigorously examines the MTM's characteristics. The antenna system showcases impressive technical attributes, including an extensive 8.7 GHz bandwidth, notably highlighting mu-near-zero (MNZ) characteristics spanning over 8.7 GHz wide frequency spectrum, and epsilon near zero (ENZ) properties covering 8 GHz (26–34 GHz). Notably, a 4-ports MIMO antenna design is adopted with each element meticulously crafted using a 4-unit cell array configuration. The designed 4 × 4 MIMO antenna is fabricated using Rogers RT/duroid 5880 substrate and it occupies a compact dimension of 45.5 × 45.5 × 0.8 mm3. Experimental validation reveals compelling performance metrics, including a bandwidth spanning from 24.3 to 30.9 GHz, isolation levels below − 25 dB, and a maximum peak gain of 15.48 dBi. Additionally, the antenna exhibits circular polarization characteristics, maintaining an axial ratio below 3 dB within the frequency bands of 25.35 to 28.05 GHz and 28.10 to 29.83 GHz. Furthermore, the fabricated MIMO antenna demonstrates outstanding diversity parameters, exemplified by a high diversity gain (DG > 9.99), low envelope correlation coefficient (ECC < 0.0001), minimal channel capacity loss (CCL < 0.5), and total active reflection coefficient (TARC < − 8 dB). The suggested MTM-based MIMO antenna system with sophisticated design and exceptional performance could be an exemplary choice for seamless integration into the evolving landscape of 5G NR networks, particularly those operating within the n257/n258/n261 bands. [ABSTRACT FROM AUTHOR]

Signal loss remains a persistent challenge in communication systems, impacting Multiple Input Multiple Output (MIMO) systems, especially in the millimeter-wave (mm-Wave) context. This paper explores the effectiveness of the proposed Hybrid Precoding/Combining Design (HPCD) algorithm within a fully connected structure of an mm-Wave downlink massive MIMO system. The primary objective is to enhance the overall system's performance, specifically focusing on improving spectral efficiency. Simulation results consistently demonstrate the superiority of the HPCD algorithm over state-of-the-art techniques, revealing substantial improvements in spectral efficiency. This thorough examination highlights the potential of the proposed approach, positioning it as a compelling solution for next-generation communication networks. The findings are anticipated to significantly contribute to spectral efficiency optimization, facilitating the seamless integration of the proposed technique into practical communication scenarios. [ABSTRACT FROM AUTHOR]

This manuscript proposed a compact four-port multiple input multiple output (MIMO) antenna based on four split-ring resonators (SRR) at the top and a defected ground structure (DGS) at the bottom of the substrate for 5G communication. SRRs are used to resonate at 4 GHz frequency in mid-5G band. A slot of " + " symbol is cut at the bottom (DGS) to enlarge the bandwidth. The proposed antenna also achieved a high-5G frequency band (26.8–29.8 GHz) (n257/n258 band) by four square-shaped ring slots at the ground plane. It further enhances the bandwidth in mid-5G band (2.9–6 GHz) (n74/n75/n76/n77/n78 band) and helps to achieve a high degree of isolation between each radiating element (over 40 dB) at both the 5G bands. The size of the proposed MIMO antenna is 60 mm × 60 mm × 1.6 mm. It achieves a maximum gain of 4.59 dB, 4.32 dB at the mid-5G and high-5G band, respectively. The maximum radiation efficiencies achieved are 89%, 81% at the mid-5G and high-5G band, respectively. The diversity functionality of the antenna is also outstanding as the value of ECC is 0.01–0.42, DG is 9.6–10 dB, and TARC is less than − 10 dB measured in both the bands. The entire performance of the proposed antenna is practically verified, discussed and presented. [ABSTRACT FROM AUTHOR]

In this paper, the design of a novel horizontally polarized single‐layer antenna for 77 (GHz) automotive radar applications is4 addressed. An innovative non‐uniform zig‐zag parametrization of the antenna layout is considered to enable a more flexible control on both the impedance matching in the working frequency band and the shaping of the radiated beam pattern with respect to a standard (uniform) one without compromising the linear (horizontal) polarization of the radiated field. Such a polarization guarantees a lower back‐scattering from road pavements, resulting in a reduced amount of clutter and thus allowing a more robust target detection. Moreover, the single‐layer layout has several advantages in terms of fabrication simplicity/costs and mechanical robustness to vibrations. The design of the proposed non‐uniform zig‐zag antenna (NZA) is performed through a customized implementation of the System‐by‐Design (SbD) approach that fruitfully combines machine learning and evolutionary optimization to efficiently deal with the computational complexity at hand. An extensive numerical validation, dealing with designs of different lengths, verifies the high performance of the NZA in terms of beam direction deviation (e.g., BDD < 1 (deg)), sidelobe level (e.g., SLL < −18.2 (dB)), and polarization ratio (e.g., PR > 20 (dB)) within the working frequency band B=76:78 $\mathcal{B}=\left[76:78\right]$ (GHz), as well as its superiority over competitive designs. Finally, the realization of a prototype and its experimental test, validate the proposed NZA concept for automotive mm‐wave radar applications in advanced driver assistance systems and autonomous vehicles such as, for instance, adaptive cruise control, collision avoidance, and blind spot detection. Key Points: The non‐uniform zig‐zag antenna (NZA) PCB‐based layout enables an effective control of antenna performance for fulfilling a set of conflicting project requirements within automotive radar frameworkThe proposed SbD‐based optimization method is an effective and efficient tool for addressing the computational complexity of the design problem at handThe realization and the measurement of a prototype prove also experimentally the suitability of the NZA layout for mm‐wave radar applications [ABSTRACT FROM AUTHOR]

Summary: In this communication, a dual port printed multi‐input and multi‐output (MIMO) antenna with high isolation of dimension 12 × 8.5 × 0.8 mm3 is designed, analyzed, and investigated for 28‐GHz 5G mm‐wave applications. The metasurface layer is suspended over the MIMO antenna to convert the linearly polarized (LP) wave to a circularly polarized (CP) wave. The unit cell of the metasurface consists of a square‐shaped conducting strip with one side of diagonal points interconnected. The conducting strip and rectangular gap between the strips etched on the substrate are capable of generating the π/2 phase shifted electric field components (Ex and Ey) resulting in polarization conversion from LP to CP. The machine learning concept is used to characterize the dimensional configuration of the antenna to achieve the optimum throughput. The MIMO diversity performance parameters and antenna essential results are validated by the measured counterparts. [ABSTRACT FROM AUTHOR]

Summary: A novel antenna system that utilizes multiple‐input and multiple‐output (MIMO) technology to suit the requirements of 5G applications is proposed in this article. The antenna has a wide operating bandwidth and high isolation in n257/n258/n261 5G bands. The suggested arc‐shaped MIMO antenna is composed of four similar patch units with modified ground planes arranged in a four‐port configuration and is made on a Rogers RT/duroid 5880 substrate, which measures 31.891 × 37.5885 × 0.508 mm3. The prototype of the suggested MIMO antenna is realized to confirm the obtained simulated results and validate the proposed design. The four‐port MIMO antenna features a broad frequency range of 7.3 GHz from 21.8 to 29.1 GHz, a peak gain of 5.76 dBi at 29 GHz, and a good isolation less than −18 dB. The proposed antenna's MIMO performance is evaluated by analyzing several diversity parameters. The findings of the evaluation demonstrate an envelope correlation coefficient (ECC) value of less than 0.001, a diversity gain (DG) value exceeding 9.995 dB, and an average mean effective gain (MEG) of −3 dB within the operational frequency band. The suggested MIMO antenna's compact size and impressive performance make it a suitable choice for intended n257/n258/n261 5G NR networks. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study of Class‐‐E/F2 and inverse Class‐‐F power amplifiers (PAs) designed for 35–42 GHz millimeter‐wave applications, utilizing a 130 nm CMOS process. The proposed RF PAs are well suited for wide frequency‐band millimeter‐wave and 5G radio transmitters. A comprehensive study of limiting factors in amplifier efficiency is presented in this paper. The study encompasses an analysis of all the factors that restrict the efficiency of the switched power amplifier. The first proposed power amplifier is based on the Class E/F2 architecture, comprising a parallel capacitor, second harmonic resonance circuit, and output matching network. Conversely, the second suggested power amplifier is constructed using the inverse Class‐‐F topology, which includes harmonic termination and matching networks. The harmonic termination circuit incorporates a second harmonic resonance network and utilizes a parasitic capacitor to control the harmonic components. Both the proposed Class E/F2 and inverse Class‐‐F architectures are employed to reshape the drain current and voltage waveforms, aiming to reduce the overlap between them and, consequently, improve efficiency. The suggested power amplifiers comprise a driver Class‐‐AB stage and a power stage constructed based on either the Class E/F2 architecture or inverse Class‐‐F topology, utilizing harmonic termination networks at the output load. Two new designs of high‐Q factor on‐chip finger capacitors have been implemented to improve efficiency and radio frequency performance. Achieving input matching and inter‐stage matching is facilitated by employing two novel on‐chip transformers designed for maximum power transfer. Additionally, an inter‐stage matching inductor is utilized in a cascode configuration to enhance the overall RF performance. The on‐chip transformers, inductors, and finger capacitors are designed using the HFSS software program. S‐parameter files (SNP files) of the designed on‐chip components are extracted and inserted into the simulation tool to ensure accurate results. The proposed Class E/F2 power amplifier achieves a constant power of 14.9 dBm, an extreme power added efficiency (PAE) of 11.7%, and a maximum gain of 13.74 dB. In contrast, the suggested inverse Class‐‐F power amplifier attains a constant power of 15.4 dBm, a peak PAE of 12.6%, and a maximum gain of 14.8 dB. The DC power consumption is 73 and 66 mW for the proposed Class E/F2 and inverse Class‐‐F PAs, respectively, while their active sizes are 0.14 and 0.2 mm2. [ABSTRACT FROM AUTHOR]

We present a compact, filtering power divider (FPD) using integrated passive device technology (IPD) for mm‐wave applications. Our proposed FPD design integrates quarter‐wavelength coupled‐resonator bandpass filters with a Wilkinson power divider, using size reduction techniques. Coupled coplanar waveguides provide excellent coupling while occupying a small area, and metal‐insulator‐metal capacitors offer the required λ/4 phase shift without length extension. The center frequency of the filtering power divider/combiner (FPD/C) is located at 30‐GHz. We demonstrate our FPD design by fabricating four prototypes with parameter variations. The insertion loss, fractional bandwidth, and size of the FPD/C designed in this study are from 2.56 to 3.3 dB, from 9.67% to 19.4%, and from 0.592 to 0.220‐mm2, respectively. In addition, the return loss of all models at the center frequency is 28.5 dB or more, and the isolation is 16.6 dB or more. [ABSTRACT FROM AUTHOR]

This study presents a symmetrical two-element Multiple-Input Multiple-Output (MIMO) antenna that exploits a feasible spectrum for 5G millimetre structure on the ground plane.It is attained to one additional operating mode at 24 GHz. A Rogers RT5880 substrate material is used in the construction of the proposed MIMO antenna. This substrate material has dimensions of 0.064 λ × 0.012 λ (at 24 GHz), a thickness of 0.8 mm, and a dielectric constant of 2.2.The results of the testing suggest that the antenna has the potential to span a frequency range that stretches from 23.5 to 25.5 GHz (6.1%) and from 34.2 to 36.4 (8.2%) GHz. In addition, the antenna does not need the usage of a sophisticated decoupling structure in order to achieve an inter-port isolation of higher than 15 dB between the antenna components across both bands. This is possible since the antenna is dual-banded. The results that were obtained from the measurement of the antenna after it was put through its paces are as follows. The components that make up this diagram are merged together to form a single entity. An envelope correlation coefficient of less than 0.005 and a channel capacity loss of less than 0.315 bits/s/Hz are the results of analysing the diversity performance characteristics. These results are totally compatible with the criteria and norms that are taken into consideration to be acceptable as a whole. The findings demonstrate that the design can successfully transmit millimetre waves at 5G rates, which was the goal of the study. [ABSTRACT FROM AUTHOR]

This paper presents a broadband millimeter-wave (mm-Wave) low noise amplifier (LNA) designed in a 22 nm fully depleted silicon-on-insulator (FD-SOI) CMOS technology. Electromagnetic (EM) simulations suggest that the LNA has a 3-dB bandwidth (BW) from 17.8 to 42.4 GHz and a fractional bandwidth (FBW) of 81.7%, covering the key frequency bands within the mm-Wave 5G FR2 band, with its noise figure (NF) ranging from 2.9 to 4.9 dB, and its input-referred 1-dB compression point (IP1dB) of −17.9 dBm and input-referred third-order intercept point (IIP3) of −8.5 dBm at 28 GHz with 15.8 mW DC power consumption (PDC). Using the FOM (figure-of-merit) developed for broadband LNAs (FOM = 20 × log((Gain[V/V] × S21-3 dB-BW [GHz])/(PDC [mW] × (F-1)))), this LNA achieves a competitive FOM (FOM = 18.9) among reported state-of-the-art mm-Wave LNAs in the literature. [ABSTRACT FROM AUTHOR]

Fifth-generation (5G) technology is extremely important in the current context since it seeks to fix the shortcomings of its predecessors, the 4G generation. To achieve this goal, this project entails constructing a small ultra-wideband (UWB) MIMO antenna featuring an anti-parallel layout, designed for operation within the millimeter-wave spectrum. Moreover, the investigation scrutinizes and fine-tunes the mutual coupling interaction between the two elements in detail. The presented MIMO antenna occupies a small footprint of 6 × 17.37 mm2. Despite its compact dimensions, this MIMO antenna provides an impressive isolation of 65 dB, attributed to the adequate inter-element spacing and the anti-parallel arrangement. Additionally, the integration of a defected ground structure (DGS) enhances isolation by approximately 20 dB. Furthermore, the proposed MIMO antenna demonstrates a satisfactory gain of approximately 6 dBi, boasting high efficiency surpassing 96 %, and lying between 34.1 and 39.7 GHz. The proposed antenna has undergone simulation and analysis utilizing both the High-Frequency Structure Simulator (HFSS) and Computer Simulation Technology (CST) in order to confirm its utility. Based on these findings, the suggested MIMO antenna appears to be well-suited for compatibility with 5G communication systems, specifically covering the n260 band (37–40 GHz) and the Ka-band.

Towards supporting a myriad of new services and applications under highly heterogeneous operating conditions, while dynamically adapting to capacity and quality-of-service (QoS) demands, the sixth generation (6G) communication systems are required to undergo significant advances. Along with the proliferation of devices, a multitude of challenges remain towards aspired performance, versatility, security, and cost-effectiveness of next generation networks. The aim of this work is to identify said challenges and promising approaches, within the scenario of dense and complex urban deployments enabled by optical-wireless coexistence. Towards enabling such operation scenario, our 6G vision focuses on various aspects of four main innovation paradigms. First, as future systems target network capacities beyond the capabilities of current technologies, the scientific trend of pursuing radio frequencies edging towards the THz domain continues. To ensure reliable and efficient deployment and mobility under the cell densification paradigm, particularly in complex urban environments, novel approaches are required to address the challenges as latency, signal blockages, and unreliable handovers. Second, towards enabling efficient operation under the heterogeneous scenario, we highlight the cooperative coexistence paradigm as a key feature of the underlying physical layer architecture. Third, joint and holistic resource optimization is required towards dynamically optimized support of mm-wave and sub-THz operation while retaining legacy coexistence, where we consider features that may benefit from the research paths proposed within the second paradigm. Fourth, network security is identified as critical towards the market adoption of technologies proposed within the first paradigm, where we highlight aspects unique to our scenario and network vision. We provide a comprehensive overview of promising state-of-the-art approaches and identify relevant research gaps while holistically addressing the four aforementioned innovation paradigms.

A low-power single-core 24.5-to-29.1 GHz CMOS LC voltage-controlled oscillator (VCO) is presented. The proposed VCO uses an innovative differential cross-coupled architecture in which an additional pair is connected to the main pair to increase the effective transconductance, resulting in lower power consumption and reduced phase noise (PN). The proposed VCO is fabricated in a 1P9M standard CMOS process and sustains oscillation at 29.14 GHz with power consumption as low as 455 μW (650 μA from a 0.7 V supply), which is ~20% lower than a conventional CMOS LC VCO without Gm-enhanced differential pairs built through the same process (700 μA from 0.8 V supply). When consuming 880 μW (1.1 mA from 0.8 V), the proposed VCO exhibits a tuning range of 4.6 GHz (from 24.5 GHz to 29.1 GHz). Moreover, it exhibits a measured phase noise (PN) better than −106.5 dBc/Hz @ 1 MHz and −132.0 dBc/Hz @ 10 MHz, with figure-of-merit (FoM) results of 195.2 dBc/Hz and 200.3 dBc/Hz, respectively. [ABSTRACT FROM AUTHOR]

High‐performance frequency selective surfaces (FSSs) have gained attention for their spatial filtering characteristics in 5G communication systems. In this work, we propose an efficient and accurate design methodology for the FSS. Three different artificial neural network methods (ANN) are employed, and their performances are compared for analysis and synthesis purposes. Results show that GRNN has the highest performance for both training and test phase of ANN based FSS analysis and synthesis. A novel, compact, low‐profile triple band FSS unit cell is introduced, and the working mechanism is described. By applying ANN based design procedure, the unit cell dimensions to resonate at the 5G mm‐wave frequency band is extracted. A unit cell with the extracted physical dimensions is simulated with a full‐wave analysis tool. The simulation results show that the FSS has the filtering feature at the predetermined mm‐wave frequencies of the 5G communication. The prototype of the FSS is fabricated, as well. The simulations are verified experimentally with measurement results. The results show that proposed ANN based analysis and synthesis method can be an effective tool for the design of FSS band‐pass filter for 5G applications. [ABSTRACT FROM AUTHOR]

This manuscript presents comprehensive modal analysis of a compact, half-mode SIW-fed slot-coupled dual-band antenna. The Characteristic Mode Analysis (CMA) is investigated in detail and presented for the first time to analyze the radiation behavior and frequency domain characteristics of the proposed structure. The number of dominant operative modes supported by the antenna is decided based on the number eigen factors, its corresponding values, and the characteristic angles. The antenna operates at 33 and 38.14 GHz with a return loss of 20.5 and 19.5 dB, a gain of 7.9 and 6.7 dBi, and an efficiency of 90% and 88%, respectively. Measured results are in close resemblance with the CMA, considering the difference between the conventional cavity modes and the characteristic modes of the proposed planar cavity configuration. The methodology can be extended to characterize any arbitrary shape radiating geometry. [ABSTRACT FROM AUTHOR]

This paper describes a four-port MIMO antenna array design featuring bow-tie-shaped slot-loaded patches with wideband capabilities that cover the frequency range from 24.2 GHz to 30.8 GHz. The proposed antenna design is printed on an FR4 substrate and occupies an area of 25 × 24 mm2. The MIMO antenna consists of four antenna arrays that are symmetrically placed in an upper-lower configuration. The bow-tie-shaped slots loaded radiators are separated horizontally by 3.48 mm and vertically by 5.94 mm. Each antenna array contains two elements that are separated by a distance of wavelength/4. The suggested MIMO antenna array delivers a high gain of 19.09 dB at 27.8 GHz and has a bandwidth of 6.6 GHz that covers the frequency band of 24.2–30.8 GHz. The research demonstrates the quality of the proposed MIMO antenna through various diversity parameters such as mutual coupling, port correlation, diversity gain, and data rate that can be transmitted over a communication medium. The simulation results are validated and found to be consistent with the experimental results. The presented antenna covers the entire bandwidth allocated to different regions, including Europe (24.25–27.5 GHz), Sweden (26.5–27.5 GHz), USA (27.5–28.35 GHz), China (24.25–27.5 GHz), Japan (27.5–28.28 GHz), and Korea (26.5–29.5 GHz). The proposed MIMO antenna design could be an excellent option for 26/28 GHz 5G NR n257, n258, and n260 bands under mm-wave wireless communication systems. [ABSTRACT FROM AUTHOR]

A wearable millimetre-wave radar antenna operating in 24.05–24.25 GHz for imaging applications in collision avoidance to assist visually impaired people is presented. Non-uniform excitation for the series end-fed 1 × 10 array antenna is optimized in simulation achieving a modified Dolph–Chebyshev distribution, which provides improved performance in terms of beam width, Side-lobe level and Gain. Commercial RO3003 and eco-friendly polypropylene (PP) are considered as substrates for comparison purposes, being the PP electromagnetically characterized for the first time at such high frequencies. Consistent agreement between simulation and measurement results is achieved for antenna prototypes on both dielectrics. The impedance matching bandwidth is analysed for the antenna on PP also under bent conditions. The overall size of the compact, low-cost, eco-friendly and flexible antenna on PP is 98.68 × 14.4 × 0.52 mm3 and, according to literature survey, it overcomes the state of the art on wearable radar antennas at 24 GHz. [ABSTRACT FROM AUTHOR]

Summary: This article communicates a novel compact four‐element orthogonal cavity‐backed antenna for 5G applications with enhanced isolation. The proposed dumbbell‐shaped substrate integrated waveguide–multiple input/multiple output (SIW‐MIMO) antenna resonate at 5.25 GHz (sub‐6 GHz) based on vias and resonate at 27 GHz (mm‐wave) with copper filling vias using FR‐4 substrate. Both prototypes are separately designed, fabricated, and tested using same dimension (40 mm × 40 mm × 1.6 mm) as well as same radiating structure. Moreover, SIW MIMO antenna design performances are compared between FR‐4 and Rogers RT/Duroid substrate. Deployment of SIW technique in MIMO antenna minimizes the antenna footprint and mutual coupling without involving any decoupling structure. The antenna simulation characteristics of both operating bands are compared and validated with the measurement results. Furthermore, the MIMO diversity parameters are examined. [ABSTRACT FROM AUTHOR]

The mm-wave antenna, consisting of a reflector, a DGS structure, and two superstates using Taconic (CER-10) and silicon, has been presented in this article. In the proposed antenna, a DGS with a reflector and two superstates is implemented to improve the antenna performance characteristics. The designed configuration (ANT-S5) is resonating on four mm-wave bands m1=41.7241GHz (41.1102-42.347) GHz, m2=48.9655GHz (48.637-49.1061) GHz, m3=63.2414GHz (61.142-66.137) GHz, m4=76.069GHz (73.4655-78.859) GHz and the maximum achieved gain is 12.02dBi at the 41.3103GHz along with the AR<3dB bands (76.1777-77.2794) GHz, (69.662-70.509) GHz. The designed antenna has been simulated on HFSS software and is convenient for 5G mm-wave applications. [ABSTRACT FROM AUTHOR]

In response to the escalating demand for high data rates and the expanding user base, multiple input multiple output (MIMO) technology has recently become of paramount importance in addressing the imperative for high-capacity communication systems aligned with emerging standards. In this paper, a single antenna element that achieves a wideband frequency coverage by adjusting the slots ‘dimensions and a satisfactory gain of 6.4 dBi is presented. To enhance the antenna's gain and capabilities, we introduced a MIMO antenna designed to operate within the frequency range of 36.8 to 40.9 GHz. The proposed MIMO antenna configuration consists of two-element arrays etched on a compact 25.94×26.76×1.3 mm³ Rogers RT/duroid 5880 substrate. While maintaining the operational band and enhancing gain, a critical challenge involving inadequate isolation between the two antenna elements is encountered due to the confined area. To effectively tackle this issue, a parametric study on the inter element distance between antennas is conducted and Defected Ground Structure (DGS) is implemented. This refinement results in a substantial 3.6 dB enhancement in isolation, which is found to be lower than -31 dB, a notable improvement in impedance matching, and a remarkable high gain of approximately 7.7 dBi is achieved. Besides, the analysis of the MIMO metrics demonstrates that they consistently fall within acceptable ranges, with the antenna showcasing an envelope correlation coefficient of approximately 0.005 and a commendable diversity gain of around 9.99 dB. The proposed antenna's combined attributes, including its compact, simple, and low-profile design, position it as a highly promising choice for 5 G communication system and future miniature devices intended for Internet of Things (IoT) applications.

This article proposed a new triple-band transmission block metamaterial (MTM) for 5G mm-wave applications. The peak transmission-blocking attributes are achieved at 27.09 GHz, 38.71 GHz, and 41.81 GHz frequency by interconnected square split ring resonators (ISSRR). A thin Rogers RT5880 substrate material of thickness 0.79 mm is employed to design the MTM structure, and the unit cell dimension is 5 × 5 mm2. The designed metamaterial shows a −10 dB transmission coefficient (S21) from 24.60 to 28.47 GHz, 36.50–39.65 GHz and 40.77–44 GHz frequency bands. The design evolution, metamaterial properties, surface current distribution, electric field, magnetic field, and equivalent circuit model are investigated to understand the transmission-blocking property of the MTM. The simulated results of the MTM are validated by measurement of the fabricated prototype, and both results agree well. The transmission-blocking attributes lead the proposed MTM as a potential candidate for different fields like EMI shielding, sensing, and antenna performance enhancement. The dielectric sensor performance of the MTM structure is investigated for different dielectric materials. Besides, MIMO antenna performances are also investigated, and gains of 1–3 dBi, isolations of 5–10 dB, and the radiation pattern deflection angle of 45˚ are enhanced by the proposed MTM. These significant features and applications of the proposed MTM make it a special candidate for 5G mm-wave applications.

In this paper, we present the design of a millimeter-wave 1 × 4 linear MIMO array antenna that operates across multiple resonance frequency bands: 26.28–27.36 GHz, 27.94–28.62 GHz, 32.33–33.08 GHz, and 37.59–39.47 GHz, for mm-wave wearable biomedical telemetry application. The antenna is printed on a flexible substrate with dimensions of 11.0 × 44.0 mm2. Each MIMO antenna element features a modified slot-loaded triangular patch, incorporating ‘cross’-shaped slots in the ground plane to improve impedance matching. The MIMO antenna demonstrates peak gains of 6.12, 8.06, 5.58, and 8.58 dBi at the four resonance frequencies, along with a total radiation efficiency exceeding 75%. The proposed antenna demonstrates excellent diversity metrics, with an ECC < 0.02, DG > 9.97 dB, and CCL below 0.31 bits/sec/Hz, indicating high performance for mm-wave applications. To verify its properties under flexible conditions, a bending analysis was conducted, showing stable S-parameter results with deformation radii of 40 mm (Rx) and 25 mm (Ry). SAR values for the MIMO antenna are calculated at 28.0/38.0 GHz. The average SAR values for 1 gm/10 gm of tissues at 28.0 GHz are found to be 0.0125/0.0079 W/Kg, whereas, at 38.0 GHz, average SAR values are 0.0189/0.0094 W/Kg, respectively. Additionally, to demonstrate the telemetry range of biomedical applications, a link budget analysis at both 28.0 GHz and 38.0 GHz frequencies indicated strong signal strength of 33.69 dB up to 70 m. The fabricated linear MIMO antenna effectively covers the mm-wave 5G spectrum and is suitable for wearable and biomedical applications due to its flexible characteristics.

This work presents a parasitic wide band compact planar antenna for 5 G mm-wave applications. Besides having high bandwidth (5.22 GHz), the prospective antenna provides an enhanced gain of 5.23dBi which is achieved due to the reflector elements used in the design. The radiating element has a small planar rectangular geometry, with optimised dimensions of 0.342 λ0 × 0.199 λ0 × 0.005 λ0 at 28 GHz frequency of interest and has been designed and fabricated on a substrate of Rogers-RT/Duroid 5800 having a thickness of 0.147λ0 with loss-tangent of 9 × 10−4 and permittivity of 2.2. The proposed antenna operates in the frequency range of 24.71 to 29.93 GHz which falls under the n257 and n258 NR operating band of the FR2 band as defined by ITU for the millimetre wave 5 G spectrum. It is also affirmed in the study that the impedance bandwidth can be tuned by controlling the coupling gap between the radiating and parasitic patches. The measured results of the fabricated prototype of the patch are compared with the simulated results and the two results are in good agreement with each other. The pursuance of the proposed design in terms of gain, efficiency, radiation pattern, and wide bandwidth, qualifies the prototype as a viable option for mm-wave communication. [ABSTRACT FROM AUTHOR]

In this work, a compact, edge-fed modified rectangular patch size, monopole, and ultra-wideband antenna has been presented for their good suitability to millimeter (mm) wave and upper sub-6 GHz frequency range (FR2) for next-generation (5G and beyond) communications. The patch size enhancement approach has been utilized without affecting the original size of the substrate and rectangular patch. The technique provides better impedance matching at the designed frequency of 32.5 GHz. The minimum acceptable gain for an antenna to work well is 5 dBi. The proposed design achieves peak gain of 5.43 dBi and 10.86 dBi at two resonance frequencies of 32.5 GHz and 48.12 GHz within the specified ultra-wideband (UWB). The antenna has low loss as it is fabricated on a compact Rogers RT Duroid 5880 of thickness 1.6 mm. The measured reflection coefficients are found in good agreement with the simulated one. The resultant performance parameters like radiation pattern, reflection coefficient, peak gain, and − 10 dB bandwidth reveal that the antenna performs excellently within 26 to 40 GHz with excellent impedance matching at the resonance frequency. At higher frequencies, the time domain response of the proposed design is also presented. The RLC electrical equivalent circuit of the proposed design is presented at the end and validated using ADS software. [ABSTRACT FROM AUTHOR]

A compact MIMO antenna with circular polarization, high gain, wide operating bandwidth, and a compact size is designed and suggested for mm-wave 5G applications. The propounded MIMO configuration contains four patch elements of similar geometries in 4 × 4 arrangement with individual E-shaped partial ground planes. The desired range of wide operating band with circular polarization, high gain, and high isolation has been achieved by modifying the structure of each single antenna element by integrating circular and semi-circular shaped slots in presence of rectangular slots loaded partial ground planes. The suggested MIMO antenna has been fabricated on a 1.67 mm thick Rogers RT/duroid 5870 substrate of 31.5 × 38.5 mm2. The fabricated and tested prototype of the suggested antenna verifies the simulation results. The suggested MIMO configuration offers a wide bandwidth of 8.1 GHz (34.4–42.5 GHz), high peak gain of about 18.5 dB and isolation of ≤−16 dB for the full working range. Besides, the presented antenna is circular polarized. This property allows the proposed antenna to emit the electromagnetic waves with a rotating electric field which allows the signal to propagate in different directions, providing better coverage and reducing the impact of signal polarization. The proposed antenna exhibits a standard MIMO performance by offering attractive diversity parameters. The proposed MIMO antenna is appropriate for 5G NR frequency band n260 (37–40 GHz) covering the allocated bandwidth requirements of different countries including UK (37–40), USA (37–37.6), Canada (37.6–40.0), and Australia (39 GHz). [ABSTRACT FROM AUTHOR]

In this work, a novel multiple input multiple output (MIMO) array antenna system with a large bandwidth and high gain has been simulated, analyzed, fabricated, and measured. The proposed antenna is structured in 2 × 4 patch configuration along with a cross shaped ground plane loaded with four square and one circular shaped defect. The projected antenna occupies a total size of 4 3. 6 1 1 × 4 3. 6 1 1 × 0. 4 2 mm 3 . Several slots in an elliptic form have been added to the patches to achieve the required results in terms of wide bandwidth and high gain. The MIMO antenna array is fabricated and experimentally tested to confirm the simulation results. The suggested MIMO array antenna offers an impedance bandwidth of 22 GHz covering 22–44 GHz wide range of frequencies with a high peak gain of 17 dBi at 38 GHz. The designed MIMO antenna offers superior diversity performance and it supports several 5G NR bands n257/n258/n259/n260/n261 in the mm-wave spectrum. The suggested MIMO antenna supports 5G application bands that are deployed in UK, USA, China, Europe, Canada, India, and Europe. [ABSTRACT FROM AUTHOR]

This article presents a quad-element MIMO antenna designed for multiband operation. The prototype of the design is fabricated and utilizes a vector network analyzer (VNA-AV3672D) to measure the S-parameters. The proposed antenna is capable of operating across three broad frequency bands: 3–15.5 GHz, encompassing the C band (4–8 GHz), X band (8–12.4 GHz), and a significant portion of the Ku band (12.4–15.5 GHz). Additionally, it covers two mm-wave bands, specifically 26.4–34.3 GHz and 36.1–48.9 GHz, which corresponds to 86% of the Ka-band (27–40 GHz). To enhance its performance, the design incorporates a partial ground plane and a top patch featuring a dual-sided reverse 3-stage stair and a straight stick symmetrically placed at the bottom. The introduction of a defected ground structure (DGS) on the ground plane serves to provide a wideband response. The DGS on the ground plane plays a crucial role in improving the electromagnetic interaction between the grounding surface and the top patch, contributing to the wideband characteristics of the antenna. The dimensions of the proposed MIMO antenna are 31.7 mm × 31.7 mm × 1.6 mm. Furthermore, the article delves into the assessment of various performance metrics related to antenna diversity, such as ECC, DG, TARC, MEG, CCL, and channel capacity, with corresponding values of 0.11, 8.87 dB, −6.6 dB, ±3 dB, 0.32 bits/sec/Hz, and 18.44 bits/sec/Hz, respectively. Additionally, the equivalent circuit analysis of the MIMO system is explored in the article. It's worth noting that the measured results exhibit a strong level of agreement with the simulated results, indicating the reliability of the proposed design. The MIMO antenna's ability to exhibit multiband response, good diversity performance, and consistent channel capacity across various frequency bands renders it highly suitable for integration into multi-band wireless devices. The developed MIMO system should be applicable on n77/n78/n79 5G NR (3.3–5 GHz); WLAN (4.9–5.725 GHz); Wi-Fi (5.15–5.85 GHz); LTE5537.5 (5.15–5.925 GHz); WiMAX (5.25–5.85 GHz); WLAN (5.725–5.875 GHz); long-distance radio telecommunication (4–8 GHz; C-band); satellite, radar, space communications and terrestrial broadband (8–12 GHz; X-band); and various satellite communications (27–40 GHz; Ka-band). [ABSTRACT FROM AUTHOR]

This article proposed a new triple-band transmission block metamaterial (MTM) for 5G mm-wave applications. The peak transmission-blocking attributes are achieved at 27.09 GHz, 38.71 GHz, and 41.81 GHz frequency by interconnected square split ring resonators (ISSRR). A thin Rogers RT5880 substrate material of thickness 0.79 mm is employed to design the MTM structure, and the unit cell dimension is 5 × 5 mm2. The designed metamaterial shows a −10 dB transmission coefficient (S 21) from 24.60 to 28.47 GHz, 36.50–39.65 GHz and 40.77–44 GHz frequency bands. The design evolution, metamaterial properties, surface current distribution, electric field, magnetic field, and equivalent circuit model are investigated to understand the transmission-blocking property of the MTM. The simulated results of the MTM are validated by measurement of the fabricated prototype, and both results agree well. The transmission-blocking attributes lead the proposed MTM as a potential candidate for different fields like EMI shielding, sensing, and antenna performance enhancement. The dielectric sensor performance of the MTM structure is investigated for different dielectric materials. Besides, MIMO antenna performances are also investigated, and gains of 1–3 dBi, isolations of 5–10 dB, and the radiation pattern deflection angle of 45˚ are enhanced by the proposed MTM. These significant features and applications of the proposed MTM make it a special candidate for 5G mm-wave applications. [ABSTRACT FROM AUTHOR]

This paper explores the evolution from 5G to 6G cellular communication technologies and their integration into the Fourth Industrial Revolution (Industry 4.0). It assesses 5G transmission techniques and anticipates advancements like NOMA with SC-FDE for spectral efficiency. Key 5G features include mm-wave, microwave, and m-MIMO. 5G enables IoT, V2V communication, and transformative technologies like autonomous driving and smart cities. The study offers insights into 6G, highlighting VR, AR, holography, advanced IoT, AI applications, wireless BCI, and high-speed mobility. It emphasizes 5G and 6G integration in Industry 4.0, shaping future industries and economies. The paper also examines post5G trends, indicating reliance on new MIMO techniques and terahertz bands for emerging applications. [ABSTRACT FROM AUTHOR]

This paper presents the design of a pseudomorphic high electron mobility transistor (pHEMT) self-oscillating mixer (SOM) for millimeter wave wireless communication systems. The 180° out-of-phase technique is chosen to both improve the desired lower sideband (LSB) signal and to achieve a satisfactory rejection of the unwanted signals (LO, USB and IF). This SOM is designed on the PH15 process of UMS foundry which is based on 0.15 µm GaAs pHEMT. The signal is up-converted from 2 GHz-IF frequency to 26 GHz-LSB frequency, using an autogenerated 28 GHz-LO signal. Simulations were performed using the advanced design system (ADS) workflow. They show 6.4 dB conversion gain and a signal rejection rate of 29.7 dB for the unwanted USB signal. the chip size is 3.6 mm². [ABSTRACT FROM AUTHOR]

With this paper, a novel 2 × 2 Multiple Input Multiple Output (MIMO) antenna for forthcoming 5G applications is introduced. The design of the MIMO antenna comprises of four modified rectangular patches and a perforated ground plane, achieved through circular and rectangular patterns, to meet the desired objectives. The antenna is constructed on Roger RT/duroid 5880 substrate, with physical measurements 35×30×0.8mm3 and a dielectric constant of 2.2. The proposed antenna has undergone simulation and analysis utilizing both the High-Frequency Structure Simulator (HFSS) and Computer Simulation Technology (CST) in order to confirm its utility. The antenna has a wide spectrum of 8.9 GHz resonating from 34.8 to 43.7 GHz. The suggested antenna has a peak gain of approximately 10.24 dBi at 38.70 GHz. Additionally; it has an isolation below −20 dB. The MIMO antenna that has been simulated exhibits strong diversity characteristics, including a low envelope correlation coefficient (ECC < 0.0002), minimal channel capacity loss (CCL < 0.4), a significant reduction in total active reflection coefficient (TARC < −8 dB), and a substantial diversity gain (DG > 9.999). The suggested MIMO antenna covers the n260 band (37–40 GHz) and the n259 band (39.5–43.5), which is widely used in different countries, such as the USA, Canada, Korea and Australia. All these findings and the small size demonstrate the capabilities of the designed antenna for future 5 G applications.

Millimeter Wave (mm-wave) technology is a prerequisite to ensure ubiquitous wireless communication, given the rapid growth of the Internet of Things (IoT) infrastructure that integrates emerging technologies such as virtual reality (VR), artificial intelligence (AI), etc. However, to ensure the future growth and acceptance of this technology, a highly efficient mm-wave compatible transceiver hardware is essential to be developed. A low noise amplifier (LNA) is one of the modules that directly influences the performance of an IoT transceiver. Numerous approaches have thus far been deployed in LNA design, such as differential cascode topology, active inductor, embedded input balun, transformer-based feedback, current reuse, stacked structure, and body biasing, to standardize various parameters e.g. die area, gain, noise figure, linearity, and power efficiency. Although complementary metal–oxide–semiconductor (CMOS) technology-based current LNA architectures in the mm-wave range suffer from substrate losses and device parasitic, it is regarded as a competitive solution for THz communication due to its inherent benefits of low-cost integrity, which promotes CMOS LNA design as an emerging research topic. This review presents several CMOS LNA architectures and perceives the adjustments of circuit topologies to ratify LNA structures in mm-wave applications. Furthermore, various state-of-the-art LNA design features are compared to envision CMOS LNA design directions and identify apposite circuit techniques suitable for the imminent 6G communication protocol. Therefore, this review will serve as a comparative study and reference for the future LNA design for the mm-wave sensor transceiver applications.

This paper presents the design of a novel bandpass filter specifically tailored for 5G mm-Wave communications. The filter utilizes a rectangle loop resonator loaded with a stepped impedance line stub at its center. The overall dimensions of the filter are 11.22×13mm2. The design incorporates Rogers RT/duroid 5880 substrate with a relative dielectric constant of 2.2, a loss tangent of 0.0009, and a thickness of 0.64 mm. The resulting filter exhibits a center frequency at 22.65 GHz, with a bandwidth of 10.5 GHz and a fractional bandwidth (FBW) of 46.36%. The reflection coefficient is approximately -39.12 dB, while the insertion loss of about -0.59 dB. We conducted a parametric study to choose the optimal value concerning the form and size of the introduced slot. To evaluate the filter's performance, simulations and assessments were carried out using the High-Frequency Structure Simulator (HFSS). The obtained results demonstrate the filter's suitability for 5G applications in various countries, including the United States (24.75-25.25 GHz), United Kingdom (26 GHz), Australia (24.25-27.5 GHz), Canada (26.5-27.5 GHz), Europe (24.5-27.5 GHz), China (24.75-27.5 GHz), Japan (26.6-27 GHz), and India (24.25-27.5 GHz).

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This article explores the development and fine-tuning of a mm-wave MPA (microstrip patch antenna) featuring silo slots. The starting design parameters are computed using established formulas relevant to patch antenna construction. The antenna is simulated on a substrate with specific material properties, utilizing Rogers 5058 substrate material characterized by a (a) of 2.2 and a tangent-loss of 0.0009. A comparative analysis is conducted to showcase the simulated performance of the presented silo-antenna using HFSS with its equivalent circuit model implemented in AWR. This involves meticulous adjustment of components to achieve the desired characteristics. The article traces the evolutionary phases of the antenna's design, highlighting geometric modifications and alterations to the ground plane. Further, it elaborates on the resonant frequencies of the antenna and offers a comparative assessment of the Su parameter between AWR and HFSS simulations, revealing strong agreement. The proposed antenna maintains an at- tractive size of 14 mm x 12 mm and it operates at dual operating bands resonating at 28.1 GHz and 37.9 GHz, Variations in gain for different design iterations are scrutinized and finally the peak gains of 5.2 dBi and 6.5 dBi are attained for the suggested antenna at the operating frequencies of 28 and 37.9 GHz, respectively along with desired radiation patterns in E and H planes at distinct frequencies. The suggested antenna is suitable for 5G applications supporting 28/38 GHz bands in mm-wave spectrum. [ABSTRACT FROM AUTHOR]