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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]

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 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.

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]

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]

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 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 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 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 paper presents a Ka-band three-stage power amplifier for 5G communications, which has been implemented in a 150 nm GaN-on-SiC technology and adopts a Doherty architecture. The amplifier is made up of a 50 Ω input buffer, which drives a power splitter, thanks to which it delivers its output power to the two power amplifier units of the Doherty topology, namely the main and auxiliary amplifier. Finally, the outputs of the two power amplifiers are properly arranged in a current combining scheme that enables the typical load modulation of the Doherty architecture, alongside allowing power combining at the final output. The proposed amplifier achieves a small signal gain of around 30 dB at 27 GHz, while providing a saturated output power of 32 dBm, with a power-added efficiency (PAE) as high as 26% and 18% at peak and 6 dB output power back-off, respectively. [ABSTRACT FROM AUTHOR]

Any wireless communication system's performance depends on channel parameters' accuracy. The classical Rayleigh and Nakagami-m research subjects remain vital even in the most modern millimeter-wave (mm-wave) applications. This research aims to create a generalized cumulative distribution function for describing random changes in wireless channels. It is vital to have a suitable channel representation model to represent varied fifth-generation applications to ease network implementation. This study provides mm-wave measurement data at 28 GHz carrier frequencies in line of sight and non-line of sight propagation. Lognormal, Nakagami, Gaussian, Weibull, and Rayleigh distributions outperform the proposed model's universal exponential density function. The experimental data verified the introduced method. [ABSTRACT FROM AUTHOR]

The aim of the 5th generation (5G) network was to create a mobile communication network that is fast, reliable, and designed to meet the future needs of society. This study introduces a compact antenna with simple slot shape and high gain, compared to other works, that operates at 28 GHz and is suitable for millimeter-wave applications within the 5G frequency spectrum. New optimized 1x4 slotted array antenna is designed using CST to operate at 28 GHz, using Rogers 5880 substrate, with height of 0.508mm, tangent loss of 0.0009 and dielectric constant of 𝜀𝐫 = 𝟐. 𝟐 and overall dimension of 12x12 mm2, for 5G mobile applications. The 1x4 slotted linear array antenna achieved a high gain of 12.6 dB at 28 GHz with 10 dB bandwidth of 0.82 GHz, and estimated radiation efficiency value of about 83% at the considered frequency of 28 GHz. So, the proposed antenna array in this research work is a strong candidate to be used in future 5G mobile phones. [ABSTRACT FROM AUTHOR]

This paper presents a 5G new radio (NR) FR2 beamforming system with an integrated transceiver module. A real-time operating module providing enhanced flexibility and capability has been proposed. The integrated RF beamforming system with an integrated transceiver module can be operated in 8Tx-8Rx mode configuration simultaneously. A series-fed structure 8 × 7 microstrip antenna array for compact size and improved directivity is employed in the RF beamforming module. The RF beamforming module incorporates a custom 28 GHz, eight-channel fully differential beamforming IC (BFIC). An eight-channel BFIC in a phased-array beamforming system offers advantages in terms of increased antenna density and improved beam steering precision. The RF beamforming module is integrated with an RF transceiver module that enables the simultaneous up-conversion and down-conversion of the baseband signal. The RF transmitter module consists of a transmitter, a receiver, a signal generator, a power supply, and a control unit. The RF beamforming system can scan horizontally from −50° to +50° with a step of 10°. To achieve an optimized beam pattern, a calibration was conducted. The transmit and receive conversion gain of around 20 dB is achieved with the transceiver module. To verify the communication performance of the manufactured integrated RF beamforming system, a real-time wireless video transmission/reception test was performed at a frequency of 28 GHz, and the video file was transmitted smoothly in real time without interruption within a range of ±50°.

This work presents a symmetrical quad-element multiple-input multiple-output (MIMO) antenna that uses a feasible band for 5G millimeter waves at 38 GHz. The main radiator is a patch antenna with a rectangular shape, and the frequency it operates at is 38 GHz. Etching a three-element split-ring resonator (SRR) metamaterial unit cell onto the normal patch radiator allows for widening the resonance over the desired operating band. The suggested MIMO antenna is built on a Rogers RT5880 substrate material that measures 15 × 15 mm2, has a thickness of 0.8 mm, and has a dielectric constant of 2.2. The results of the measurements show that the antenna is capable of covering a frequency range from 37.3 to 39.3 GHz and can also achieve an inter-port isolation of greater than 20 dB between the antenna elements across both bands without the use of a complex decoupling structure. These are the results that were obtained when the antenna was tested. An equivalent circuit diagram of the electrical responses of the antenna is also presented to get insight into the proposed antenna. This schematic makes use of lumped components. The diversity performance parameters that were analyzed provide an envelope correlation coefficient that is less than 0.005, and a channel capacity loss that is less than 0.35 bits/s/Hz. All of these results fall well within the parameters that are considered acceptable norms. The findings provide evidence that the design is workable for the transmission of millimeter waves at 5G speeds. [ABSTRACT FROM AUTHOR]

The fifth-generation (5G) cellular networks will provide gigabit-per-second data rates from massive antenna array combined with the emerging use of large and unexploited millimeter wave (mm-Wave) bands (30–300 GHz) in small cells. Channel estimation for sparse mm-Wave MIMO systems is a difficult task. This is because of a large number of coefficients to be estimated, lower scattering nature, and blockage of mm-Wave by many materials in the environment. This paper will be the opportunity to implement the sparse channel estimation in the 5G cellular networks. In this work, we propose compressed-sensing (CS) based solutions and implements hybrid MIMO architecture for the proposed algorithm, OMP algorithm, and oracle estimator with different mm-Wave MIMO setups. Simulation results show that as compared to the OMP algorithm, proposed algorithm requires 16.9 times less computation time, and significant improvement is seen in normalized mean squared error (NMSE). Also, in the analysis, we found that the performance of the hybrid MIMO approaches near-optimal to conventional fully digital precoder. [ABSTRACT FROM AUTHOR]

In this paper, an antenna with a multiple-input, multiple-output (MIMO) configuration is demonstrated for mm-wave 5G-based Internet of Things (IoT) applications. The two antenna elements are arranged next to each other to form a two-port antenna system such that significant field decorrelation is achieved. Moreover, a dielectric layer is backed by an eventual multiport system to amend and analyze the radiation characteristics. The overall size of the MIMO configuration is 14 mm × 20 mm, and the operation bandwidth achieves ranges from 16.7 to 25.4 GHz, considering the −10 dB criterion with a maximum isolation of more than −30 dB within the operating band. The peak gain offered by the antenna system is nearly 5.48 dB, and incorporating a dielectric layer provides an increase in the gain value to 8.47 dB. Within the operating band, more than 80% total efficiency is observed, and analysis shows several MIMO performance metrics with favorable characteristics. The compactness of the proposed design with high isolation, improved gain, and wideband features make it a suitable candidate for mm-wave-based 5G applications. [ABSTRACT FROM AUTHOR]

The current and future wireless communication systems, WiFi, fourth generation (4G), fifth generation (5G), Beyond5G, and sixth generation (6G), are mixtures of many frequency spectrums. Thus, multi-functional common or shared aperture antenna modules, which operate at multiband frequency spectrums, are very desirable. This paper presents a multiple-input and multiple-output (MIMO) antenna design for the 5G/B5G Internet of Things (IoT). The proposed MIMO antenna is designed to operate at multiple bands, i.e., at 3.5 GHz, 3.6 GHz, and 3.7 GHz microwave Sub-6 GHz and 28 GHz mm-wave bands, by employing a single radiating aperture, which is based on a tapered slot antenna. As a proof of concept, multiple tapered slots are placed on the corner of the proposed prototype. With this configuration, multiple directive beams pointing in different directions have been achieved at both bands, which in turn provide uncorrelated channels in MIMO communication. A 3.5 dBi realized gain at 3.6 GHz and an 8 dBi realized gain at 28 GHz are achieved, showing that the proposed design is a suitable candidate for multiple wireless communication standards at Sub-6 GHz and mm-wave bands. The final MIMO structure is printed using PCB technology with an overall size of 120 × 60 × 10 mm3, which matches the dimensions of a modern mobile phone.

A modular dual-polarized Vivaldi antenna array design for 18–30 GHz frequency is presented. The array module consists of the antenna and RF modules. The antenna module comprises $4\times 4$ dual-polarized antenna elements with element spacing of $\lambda $ /2 at 30 GHz. The RF module contains the amplifiers and phase shifters that control all the elements using commercial off-the-shelf (COTS) flip-chip components. The footprint of the RF module is the same as that of the antenna module allowing assembly of antenna arrays of almost any size and shape. Additionally, the interface between the antenna and the RF modules is connectorless, decreasing the number of components required in the assembly and decreasing the overall cost of the system. An array of $4\times 8$ dual-polarized antenna elements is constructed from two array modules to prove the seamless operation of the modular design. The prototype uses Anokiwave chips with a frequency range from 26.5 GHz to 29.5 GHz. The measured amplitude and phase of the electric field in front of the antenna aperture is uniform so as to equally feed the elements. Additionally, the demonstrated beam steering up to ±60° in the plane of the larger array dimension matches well with the simulations, proving the feasibility of the design.

• The dielectric properties of silicates are frequency independent from 5 GHz up to around 40 GHz • The dielectric properties of silicates show two resonances at higher frequencies - the boson peak around 2 THz and the Si-O-Si bending vibration around 13 THz • Constructing Cole-Cole plots at THz provided insight into the boson peak and ionic resonance relaxation dynamics [Display omitted] In this paper, a broadband measurement of the dielectric properties of silicates has been done to cover the seldom characterized mm-wave spectrum and the low THz spectrum. The dielectric properties, i.e. loss and permittivity, show a frequency independent response up to approximately 40 GHz and the loss monotonically increases to the THz frequency range. Two resonance peaks appear at THz frequencies: the first is the boson peak, and the second one corresponds to the ionic resonance of the network former, which in this case is silicon. Even though the materials belong to different groups in the silicate family (crystalline and non-crystalline, with different levels of purity), they seem to have the same overall tendency in the dielectric properties. Argand plots are used for the first time at THz frequencies to provide physical insight into the boson peak and ionic resonance. The complex plane analysis reveals details on the polarization mechanisms underlying silicate network vibrations through direct visualization of their characteristic signatures, and simplifies the process of modeling the dielectric response, leading to a better fit. [ABSTRACT FROM AUTHOR]

In this work, we present a new class of thickness extensional microelectromechanical resonator, the overmoded bulk acoustic resonator (OBAR) for filtering applications in the 5G millimeter wave (mm-wave) spectrum. This resonator operates in a second overtone thickness mode with approximately equal thickness electrodes and piezoelectric layer so that acoustic energy is distributed evenly between the different layers. Compared to a fundamental mode at a fixed frequency, the OBAR possess a $3\times $ thicker piezo layer and 5– $10\times $ thicker metal electrodes, enabling manufacturable 30–60 GHz devices. We demonstrate the OBAR experimentally through fabrication of a Pt-AlN-Al device with electromechanical-coupling coefficient ($k_{t}^{2}$) of 1.7%, and series resonance quality factor ($Q_{s}$) of 110 at 33 GHz. [ABSTRACT FROM AUTHOR]

This paper presents a compact dual-band and dual-polarized millimeter-wave patch antenna array with satisfactory performance on element mutual coupling and beam scanning capabilities. Using capacitive feed technique and stacked configuration with extra parasitic strips, the proposed antenna array is able to achieve a wide operating bandwidth in both the low- and high-bands. In order to reduce the array’s footprint, and to enhance the beam scanning performance in both bands, the element spacing is shrunk to less than 0.36 wavelength at 26 GHz. To improve the isolation between array elements due to their small spacings, two effective decoupling approaches are adopted, which result in a 6-dB isolation enhancement. The overall size of the proposed antenna array is only 18.2 mm $\times4.1$ mm $\times1.07$ mm, which is smaller than some industrial mm-Wave antenna modules released recently. Our simulation shows that the antenna array can fully cover the 5G NR bands of n258~n261 simultaneously. The four-element array provides ±60° and ±45° beam scanning performance in the low- and high-bands, respectively. The experimental data of reflection coefficient, mutual coupling, and radiation patterns confirm with the simulated results, rendering the proposed array to be a good candidate for 5G mm-Wave communications.

This paper presents a fully integrated linear power amplifier (PA) in a 65-nm CMOS process for mm-wave 5G applications. The proposed linear PA employs a compact symmetrical 4-way parallel–parallel power combiner with a third-order intermodulation distortion (IMD3) cancellation method to achieve high linear output power with a high power-added efficiency (PAE). An on-chip 4-way parallel–parallel power combiner, which combines the output power from 8-unit PAs, is designed with a compact footprint ( $241\,\,\mu \text{m}\,\,\times 241\,\,\mu \text{m}$ ). Conventional series power-combining transformer based power combiners have poor symmetrical performance for the amplitude and phase of the input impedance among unit PAs owing to the parasitic effects of the power combiners. However, the proposed parallel–parallel power combiner, which is based on parallel power-combining transformer structures, shows good symmetrical performances among unit PAs. Moreover, an IMD3 cancellation method using a parallel–parallel power combiner is proposed in this work. The proposed IMD3 cancellation method can support high-order modulation signals without increasing the complexity and reduce the dependence for digital predistortion (DPD). Consequently, the proposed linearization method obtains a high linear POUT and PAE without DPD. The PA in 65-nm CMOS demonstrates a saturated output power (PSAT) of 23.2 dBm, a 15.9-dB power gain, a 1-dB compressed output power ( $\text{P}_{\mathrm {O,1dB}}$ ) of 22 dBm, and a peak power-added efficiency (PAE) of 33.5% at 28 GHz. The measured error vector magnitude with 100 Msym/s of 256/512-QAM is −31.2/−32.1 dB with average output power of 18.02/17.73 dBm, average PAE of 17.6/16.1%, and adjacent channel power ratio (ACPR) of −30/−33.1 dBc without DPD. To the best of the authors’ knowledge, the proposed PA demonstrates high output power with the highest PAE performance supporting 256/512-QAM compared to the recently published fully integrated mm-wave 5G CMOS PAs.

The deployment of the Millimeter-Wave (mm-Wave) band in 5G and beyond wireless communications networks is one of the emerging fields owing to its potential of providing extensive bandwidth. Frequency Hopping (FH) has a high potential for use in wireless networks due to its key advantages of spreading the interference over wide bandwidth and of providing diversity gain in counteracting frequency-selective fading. Furthermore, Fast Frequency Hopping (FFH) intrinsically amalgamated with directional Beamforming (BF) may overcome the impairments because of the path-loss of mm-Wave communications. Thus, we propose FFH assisted base-band precoding aided BF for mitigating the mm-wave channel impairments imposed by both fading as well as path loss, whilst relying on a minimal range of radio frequency chains. The mathematical analysis and simulation results demonstrate that hybrid precoded FFH is indeed a promising high-capacity technique of attaining both time- and frequency-domain diversity gains for the mm-Wave communications.

A dual-band quad-polarized transmitarray (TA) is designed in a common aperture operating at 25.9/39.8 GHz. Using narrow strip patches as cells, the 25.9 GHz cells are arranged in the ±45° direction, and the 39.8 GHz cells are arranged in the 0/90° direction in the formed square gap of the 25.9 GHz cells to realize a compact design with four polarization directions. In each band of 25.9/39.8 GHz, the proposed TA is dual-polarization designed. Measurements show that the expected beams can be achieved, and their 3 dB gain bandwidth covers almost all of the 5G bands n258 (24.25–27.5 GHz) and n260 (37–440 GHz). This TA has potential application value in 5G construction.

A high-isolation wideband MIMO (Multiple-Input Multiple-Output) antenna, shaped like a palm tree, is designed for 5G wireless communication purposes. The propounded MIMO antenna is formulated on an FR4 substrate, featuring a quartet of ports and adhering to a precise dimension of 45 × 50 × 0.8 mm3. A detailed analysis of the proposed high isolation wideband palm tree shaped MIMO antenna, considering its bandwidth, gain, isolation, radiation patterns, and diversity performance metrics such as diversity gain, channel capacity loss, mean effective gain, and total active reflection coefficient, is presented. The results obtained from simulations and measurements demonstrate good agreement, indicating the antenna's effectiveness for intended applications. Indeed, an extensive bandwidth covering a range of 11.6 GHz from 23.4 GHz to 35 GHz is achieved by demonstrating superb reflection coefficient. Additionally, the design reports remarkable isolation and a peak gain of 12.4 dB, indicating its ability to enhance signal strength. One of the most notable features of this MIMO antenna is its coverage of multiple 5G bands, making it ideal for use in various geographical regions, including the USA and Canada (27.5–28.35 GHz, 37.0–37.6 GHz, and 37.6–40.0 GHz), China (24.75–27.5 GHz), Korea (28–39 GHz), Japan (27–29.5 GHz) and Sweden (26 GHz). [ABSTRACT FROM AUTHOR]

This paper is concerned with dual-band electronically beam-scanning for millimeterwave (mm-wave). A design encompassing slotted square patch antenna with an Active Frequency Selective Surface (AFSS) screen is presented. Each unit cell of AFSS is constructed of spiral arms endorsed with four varactors to enhance a wide tuning range over dual modes. Among many other features, the design supports dual operation bands at 48.5 and 68.5 GHz which is considered without any 90° phase shifter and is excited by a single-feed microstrip line. The overall size of the proposed antenna is only 3.93.90.1 mm3, which is smaller than some mm-wave antenna modules released recently. The whole structure is an ideal option for wireless applications due to its ability to scan its primary beam in dual-band throughout the whole azimuth plane with a resolution of 60°. The proposed structure can sweep beams throughout the whole 360° angular range and is capable of both dual-band and single-band beam sweeping with high gain, making it an excellent choice for 5G mm-wave applications. [ABSTRACT FROM AUTHOR]

A planar inverted-F antenna with symmetrical split beams and loaded with radio frequency absorbers (here Eccosorb MCS) for 5G communication is proposed. The multi-beam antennas reduce the requirement of number of antennas and provide wide coverage. But they require a complex system such as a phased array or MIMO antennas. On the other hand, multi-beam antennas do not have such requirements. In this work, we propose a PIFA antenna which achieves multi-beam behaviour by six slabs of absorbers placed periodically between the PIFA patch and substrate to split the beams into two directions at +26°. The proposed antenna obtains a frequency band of 24.2- 25.7 GHz and achieves a high gain of approximately 10 dB at +26°. The performance of the proposed antenna is suitable for G communication. All simulations of the antenna are carried out using Ansys HFSS. The design was validated by simulations and later confirmed with measurements. [ABSTRACT FROM AUTHOR]

Stacked nanosheet nFETs considering a six-stack four-finger transistor array are studied and optimized by validated TCAD simulation. Stacked Si nanosheet (NS) nFETs have lower parasitics than nFinFETs in the same six-fin/stack four-finger transistor array layout. With the same electron mobility, back-end-of-line (BEOL), equivalent oxide thickness (EOT) of 1.4 nm, and gate length of 30 nm, the stacked Si NSs have $1.1\times $ cut-off frequency (240 versus 215 GHz) and $1.15\times $ maximum oscillation frequency (290 versus 251 GHz) when compared to FinFETs due to larger transconductance increase than capacitance increase and output conductance decrease. With the optimized EOT of 0.8 nm and gate length of 18 nm, the stacked Si NSs can achieve cut-off frequency of 340 GHz and maximum oscillation frequency of 370 GHz. Furthermore, considering the higher electron mobility on {100} surfaces of NSs than {110} sidewalls of FinFETs as suggested by the ${I} _{D}$ – ${V}_{\text {GS}}$ fitting, the cut-off frequency and maximum oscillation frequency of stacked Si NSs can reach 380 and 390 GHz, respectively. [ABSTRACT FROM AUTHOR]

Wafer level chip scale package (WLCSP) is true chip scale package with low cost by eliminating package substrate. The direct chip-to-board attach through solder joints provides low interconnect inductance and resistance, as well as improved thermal performance. These properties make WLCSP a packaging format well suited for 5G radio frequency (RF) applications where minimized package size and parasitics as well as thermal performance are critical. Due to the dissimilar properties between chip and board, the reliability of WLCSP can be challenging. This article reports a reliability study of WLCSP using 45nm RFSOI technology for 5G RF applications. Dedicated test chips and boards were designed and used for board level reliability tests. The test vehicles passed bHAST and drop test, whereas it is found that temperature cycling on board (TCoB) is challenging for solder joint reliability in some cases. Thorough tests were carried out based on Kelvin test on specially designed individual bump and bump pair structures and developed fail criterion. Finite element modeling was adopted to simulate the reliability performance in different configurations. The impact on reliability performance from bump depopulation, die thickness, bump size, UBM to board pad alignment, and board wiring trace were thoroughly investigated. Based on comprehensive testing and deep understanding of the failure mechanisms, design optimizations for chip, board and interconnect were implemented. WLCSP reliability was significantly improved.