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A millimeter-wave (mm-wave) antenna with enhanced gain for new 5G networks is introduced in this work. A rectangular slot antenna operating at the fundamental mode of the desired frequency band is utilized in this study. The antenna gain is improved by employing a Frequency Selective Surface (FSS). The FSS-based reflectors are designed at the same fundamental mode of the antenna and added under the antenna at a specific distance to achieve the required gain enhancement with a suitable dimension of 25 $\times 25\times5$ mm3. The antenna gain is increased by around 5.3 dBi when the FSS-based reflectors are added under the antenna. The antenna and the FSS are fabricated and tested. The antenna has tested outcomes without FSS with S11 ≤ −10 dB from 26 GHz up to 29.8 GHz and realized gain of around 4.5 dBi within the entire frequency band and radiation efficiency of around 93 %. While the antenna with FSS has achieved bandwidth with S11 ≤ −10 dB from 25.5 GHz up to 30.8 GHz and realized gain around 10.3 dBi at 28 GHz and radiation efficiency around 90 %. The simulated and tested outcomes have the same trend which validates the suggested antenna to be operated in the new 5G applications. All simulation results are completed using the CST Microwave Studio.

Millimeter-wave (mm-wave) communication is the spectral frontier to meet the anticipated significant volume of high data traffic processing in next-generation systems. The primary challenges in mm-wave can be overcome by reducing complexity and power consumption by large antenna arrays for massive multiple-input multiple-output (mMIMO) systems. However, the circuit power consumption is expected to increase rapidly. The precoding in mm-wave mMIMO systems cannot be successfully achieved at baseband using digital precoders, owing to the high cost and power consumption of signal mixers and analog-to-digital converters. Nevertheless, hybrid analog–digital precoders are considered a cost-effective solution. In this work, we introduce a novel method for optimizing energy efficiency (EE) in the upper-bound multiuser (MU) - mMIMO system and the cost efficiency of quantized hybrid precoding (HP) design. We propose effective alternating minimization algorithms based on the zero gradient method to establish fully-connected structures (FCSs) and partially-connected structures (PCSs). In the alternating minimization algorithms, low complexity is proposed by enforcing an orthogonal constraint on the digital precoders to realize the joint optimization of computational complexity and communication power. Therefore, the alternating minimization algorithm enhances HP by improving the performance of the FCS through advanced phase extraction, which involves high complexity. Meanwhile, the alternating minimization algorithm develops a PCS to achieve low complexity using HP. The simulation results demonstrate that the proposed algorithm for MU - mMIMO systems improves EE. The power-saving ratio is also enhanced for PCS and FCS by 48.3% and 17.12%, respectively.

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.

This paper presents a transmitter (TX) and a receiver (RX) with a cross-polarized bowtie-antenna on a silicon lens for gas spectroscopy at 222–270 GHz and the doubled frequency at 444–540 GHz. TX and RX are fabricated in 0.13 μm SiGe BiCMOS technology. Both use two integrated local oscillators for frequency subbands 222–256 GHz and 250–270 GHz, which allow operating in one branch of the TX and RX at 222–270 GHz and in a second branch of the TX and RX at 444–540 GHz by frequency doubling. The directivity of the cross-polarized bowtie-antenna of the TX and RX is optimized for these two frequency bands with an estimated value of 24.4 dBi at 260 GHz, and 29.5 dBi at 520 GHz. Absorption spectroscopy of gaseous methanol is used as a measure for the performance of the TX and RX in the lower and upper frequency bands.

• 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, characterizations are performed to investigate the stability of an mm-wave GaN metal-insulator-semiconductor HEMT. Bias temperature instability (BTI) experiment conducted at various voltages and temperatures show a highly stable threshold voltage (${V}_{\text {TH}}$) with both positive BTI (PBTI) and negative BTI (NBTI) attributing to the high quality of SiN gate dielectric. In addition, ${V}_{\text {TH}}$ shift (${\Delta } {V}_{\text {TH}}$) under reverse-bias step-stress is further monitored, achieving small ${\Delta } {V}_{\text {TH}} < {0.1}$ V and a recoverable behavior below ${V}_{\text {D}}$ , stress = 60 V. After 104 s of stress at 175°C, under the OFF-state high drain-bias, ${\Delta } {V}_{\text {TH}}$ is 0.15 V, and a larger ${V}_{\text {TH}}$ shift (0.23 V) is observed under On-state drain-bias of 28 V due to the high electric-field. According to the time-dependent dielectric breakdown prediction, +3.0 V gate voltage stress at a failure rate of 0.01 % can be extrapolated for mm-wave MIS-HEMT. These findings guarantee a good stability for the device utilized in power amplifier applications. [ABSTRACT FROM AUTHOR]

Multi Input Multi Output (MIMO) and phased array systems are considered a key technologies to realize the 5G communication systems. Therefore, the purpose of this research is the suggestion of a novel mm-wave Ultrawide Band (UWB) antenna design with compact and straightforward layout suitable for both MIMO and phased array systems. Hence, the designed antenna array has been studied separately as a MIMO antenna and as a phased array antenna to carefully assess the performance of each system. The single antenna design is an elliptical patch antenna where the design novelty lies in the combination of a modified inset-feed and defected ground structure to provide a large bandwidth without any compromise in the radiation performance, nor in antenna size and design simplicity. The Design process are performed using CST MWS software, where the Rogers RT/Duroid 5880 substrate is chosen to construct the antenna. A broadband characteristic of 8.7 GHz from 26 to 34.7 GHz with two resonant frequencies at 28 GHz and 33 GHz is obtained. A good radiation properties are achieved, where the gain is greater than 4.5 dB while the radiation efficiency exceeds 97% over the operating band. The MIMO and phased array antennas are made up of 12-elements of the single UWB-antenna arranged linearly along the width-edge of the smartphone mainboard. The MIMO antenna proves a high diversity performance in terms of Diversity Gain (DG), Envelope Correlation Coefficient (ECC), Total Active Reflection Coefficient (TARC), Channel Capacity Loss (CCL) and Mean Effective Gain (MEG), owing to the low mutual coupling less than − 20 dB, which is obtained using a separating slits between the elements. In addition, the suggested phased array provides a highly stable gain up to 15 dB over the entire bandwidth at broadside direction, besides the wide scanning range of ± 60° at 28 GHz and ± 40° at 33 GHz. Hence, the attained results assure that the suggested antenna could be appropriate for incorporation in 5G smartphones and other wireless devices and can be effectively used for both phased array and MIMO applications. [ABSTRACT FROM AUTHOR]

In this paper, mm–wave low cost single and multiple input and multiple output (MIMO) planar microstrip antenna suitable for futuristic K–(18–26.5GHz), K a –band (26.5–40GHz) and local multipoint distribution systems (LMDS) applications is presented. The proposed structure achieves impedance bandwidth of 22.77 GHz (17.23–40GHz) with a peak gain of 13.69 dBi that notably covers the LMDS modern wireless communication application requirement. This achieves 5 dBi gain-bandwidth of 9.07 GHz (26.77–35.85GHz) and 17 GHz (19–36GHz) for single element and MIMO antenna with four elements in cascaded form respectively. The improvement in gain and impedance bandwidth is augmented after exciting multiple resonances of antenna by etching of two 3-armed H-shaped slots (3-AHSS) and inverted T-shaped slots (ITSS) symmetrically in the patch. With these etchings the copper losses and vertical components of current are controlled. The fabricated prototype of size 37 × 15 m m 2 is connected through a mm–wave supporting frequency connector of 2.92 mm and 50 Ω coaxial type to Vector Network Analyzer (VNA) Bench of modal number Rohde and Schwarz (ZNB–40) for measurement of performance parameters and it is found to be in good promise with simulated results. [ABSTRACT FROM AUTHOR]

The impractical association of a dedicated fiber optic backhauling link with each base station in future wireless area network (WAN) networks promoted self-backhauling to become one of the most practical techniques for ultra-dense deployments. Selfbackhauling reduces the number of stations with fiber-optic links, while the remaining stations can communicate with the core network through wireless multi-hoping connections. Nevertheless, routing through self-backhauling stations is an NP-hard problem. In this study, we propose a routing scheme based on a semi-distributed self-learning algorithm to reduce the end-to-end latency which achieve better stability against the dynamic nature of the mobile network, such as load variations and link failures. The proposed solution offers changing propagation medium between freespace optical (FSO) and radio frequency (RF); this dynamic change between every two hops reduces power consumption, increases throughput, and minimizes latency. Based on the performed simulation, our proposed algorithm measured better overall bit error rate (BER) compared to both RF-only and free-space optical FSO-only techniques resulting in increased backhauling capacity and reduced overall route interference. [ABSTRACT FROM AUTHOR]

This brief presents a comprehensive tutorial on the recent advances of injection-locking techniques used for millimeter-wave (mm-Wave) and terahertz (THz) signal generation systems. Injection locking has the potential to significantly improve the system performance in terms of low phase noise and low power consumption. The focus will be on the state-of-the-art injection-locking techniques to effectively widen the locking range and reduce the phase noise, including injection-locked frequency dividers (ILFDs), injection-locked frequency multipliers (ILFMs), and sub-harmonic injection-locked phase-locked loops (IL-PLLs). [ABSTRACT FROM AUTHOR]

This article presents a 150-GHz regenerative low-power miniature two-way radio integrated with on-chip antennas. The low-power radio is based on a reconfigurable fundamental oscillator array that can be used as a sub-terahertz (THz) source in the transmitter (Tx) mode and a sub-THz super-regenerative detector in the receiver (Rx) mode supporting ON–OFF keying (OOK) modulation. The oscillators are coupled through a low-loss integrated Marchand balun-based coupling network that guarantees far-field constructive interference at the Rx side. A 2 $\times $ 2 on-chip patch antenna array is designed with a new adaptive metal-fill placement methodology that largely reduces antenna losses and off-tuning present in sub-THz/THz frequency antenna designs without the need for bulky silicon lenses. Our proof-of-concept prototype achieves a maximum EIRP of 8.52 dBm at a frequency of 149 GHz, an Rx sensitivity of −70 dBm, and a dc-to-EIRP efficiency of 30.7% with no silicon lens, which is the highest efficiency reported of all the silicon-based sub-THz transceivers (TRxs) in the 150-GHz range. The moderate 2 $\times $ 2 array size with no silicon lens offers a large field of view (FoV) of ±40°, which eases node finding and link establishment in deployment. Our miniature low-power radio prototype consumes 11.6 mW in the Tx mode and 10 mW in the Rx mode after duty cycling. Wireless peer-to-peer network measurements with OOK modulation using a 10-Mb/s data rate demonstrate a chip-to-chip communication distance of 70 cm and BER $\le $ 10 $^{-5}$ at/above −55-dBm received power and a BER of 6 $\times $ 10 $^{-3}$ at −70-dBm received power. The prototype chip was designed using the GlobalFoundries 45-nm silicon-on-insulator (SOI) process, and it occupies a total chip area of 2.1 mm $\times $ 2.1 mm, including the antenna array, making it particularly apt for ultra-miniaturized, high-security, and stealth Internet-of-Things (IoT) nodes for intelligent edge networks and wearable devices. [ABSTRACT FROM AUTHOR]

This paper presents a compact 213 GHz fundamental oscillator with an optimal embedding network that maximizes the output power. Fabricated in 65-nm bulk CMOS, the oscillator occupies a core area of only 70×40 pm2, owing to the use of a compact low-loss capacitive transformer structure. The oscillator achieves 0.56-mW output power while consuming a DC current of 14.35 mA from a 1-V power supply, representing a recording-breaking DC-to-RF efficiency of 3.9% amongst fundamental oscillators above 200 GHz.

Interconnect materials play the critical role of routing energy and information in integrated circuits. However, established bulk conductors, such as copper, perform poorly when scaled down beyond 10 nm, limiting the scalability of logic devices. Here, a multi-objective search is developed, combined with first-principles calculations, to rapidly screen over 15,000 materials and discover new interconnect candidates. This approach simultaneously optimizes the bulk electronic conductivity, surface scattering time, and chemical stability using physically motivated surrogate properties accessible from materials databases. Promising local interconnects are identified that have the potential to outperform ruthenium, the current state-of-the-art post-Cu material, and also semi-global interconnects with potentially large skin depths at the GHz operation frequency. The approach is validated on one of the identified candidates, CoPt, using both ab initio and experimental transport studies, showcasing its potential to supplant Ru and Cu for future local interconnects., (© 2024 Wiley‐VCH GmbH.)

In the recent past, the possibility to use a superconducting trap confining a hot and dense plasma as a tool to investigate radioactivity in astrophysical scenarios has been proposed. Making possible these kind of unprecedented measurements is the main aim of the PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) project. In this context, it is planned to build a compact and flexible magnetic plasma trap where plasma reaches an electron density ne ∼ 1011–1013 cm−3, and an electron temperature, in units of kT, kTe ∼ 0.1–30 keV. The setup is conceived to be able to measure, for the first time, nuclear β-decay rates in stellar-like conditions in terms of ionization states. In this paper, the design study of a mm-wave polarimeter for the PANDORA plasma line-integrated electron density measurement is presented. The paper highlights the method of this type of measurements for the first time proposed for a magneto-plasma trap which represents an “intermediate” case between the ultra-compact plasma ion sources and the large-size thermonuclear fusion devices. Preliminary measurements at scaled microwave frequencies have carried out both on a “free-space” setup by using a wire-grid polarizer and a rotable Ka-band OMT + horn antennas system, and on a compact trap (called Flexible Plasma Trap) installed at INFN-LNS and used as PANDORA down-sized testbench are described. The polarimeter technique will support β-decay investigation by simultaneous measurements of the total plasma density, which is crucial to carefully evaluate the decay-constant and to extrapolate the laboratory observed data to the astrophysical scenarios. Moreover, this work proposes to adopt an electromagnetic inverse-scattering-based technique-based method to retrieve the electron density profile along the probing antennas line-of-sight. Numerical results of this so-called “inverse profilometry” are also shown.

In geometrical localization techniques, the propagated signal’s first-order multipath (FOMP) characteristics are used to calculate the location based on geometrical relationships. Utilizing the characteristics of higher order multipath (HOMP) results in a significant localization error. Therefore, distinguishing between FOMPs and HOMPs is an important task. The previous works used traditional methods based on a deterministic threshold to accomplish this task. Unfortunately, these methods are complicated and insufficiently accurate. This paper proposes an efficient method based on supervised learning to distinguish more accurately between the propagated FOMP and HOMP of millimeter-Wave Vehicle-to-Vehicle communication in an urban scenario. Ray tracing technique based on Shoot and Bounce Ray (SBR) is used to generate the dataset’s features including received power, propagation time, the azimuth angle of arrival (AAOA), and elevation angle of arrival (EAOA). A statistical analysis based on the probability distribution function (PDF) is presented first to study the selected features’ impact on the classification process. Then, six supervised classifiers, namely Decision Tree, Naive Bayes, Support Vector Machine, K-Nearest Neighbors, Random Forest, and artificial neural network, are trained and tested, and their performance is compared in terms of HOMP misclassification. The effect of the considered features on the classifiers’ performance is further investigated. Our results showed that all the proposed classifiers provided an acceptable classification performance. The proposed ANN showed the best performance, whereas the NB was the worst. In fact, the HOMP misclassification error varied between 2.3% and 16.7%. The EAOA exhibited the most significant influence on classification performance, while the AAOA was the least.

The application of millimeter-wave (mm-wave) frequencies in communication has the potential to address the ever-growing data traffic requirements of next-generation wireless communication devices. However, owing to their high directivity and high penetration loss, directional mm-wave beams are vulnerable to blockages caused by users' bodies and ambient obstacles. Further development of indoor mm-wave communication is essential, as the majority of data traffic is generated in indoor environments. In previous studies, the mm-wave blockage problem was primarily considered in outdoor scenarios, whereas in the present study, online learning-based beam and blockage prediction in an indoor hotspot (InH) scenario was investigated. During an offline training phase, we constructed a fingerprinting database consisting of user locations along with their respective data traffic demands and corresponding blockage statuses with optimal beam indices. Following its creation, the fingerprinting database was used to train the weights and bias of a properly designed deep neural network (DNN). During a subsequent online learning phase, the trained DNN was fed user locations and corresponding data traffic demands at the served user equipment to output optimal beam indices and blockage statuses. System-level simulations were conducted to assess the accuracy of blockage prediction based on 3GPP's new radio channel and blockage models in InH environments. Simulation results revealed that the proposed scheme was capable of predicting mm-wave blockages with an accuracy of > 90%. These results confirmed the viability of the proposed DNN model for predicting optimal mm-wave beams and spectral efficiencies. [ABSTRACT FROM AUTHOR]

This brief presents the modeling and design of a static current-mode logic, divide-by-2 frequency divider for mm-wave frequency synthesis. An optimized design procedure based on the $RC$ delay model and insights into the nonlinear mixing conversion gain of the injection-locking model are presented and leveraged towards the design of an inductor-less 28-nm CMOS prototype that achieves 72 GHz maximum input frequency and power-delay product of 21.5 fJ. Performance can be tuned to 66 GHz and 16.9 fJ, respectively, via lowering the supply voltage. In addition to standalone measurements with an off-chip input signal, a fundamental-frequency dual-core voltage-controlled oscillator provides on-chip and realistic input signal generation. [ABSTRACT FROM AUTHOR]

Deep learning and artificial intelligence, in general, is advancing scientific discovery and technological inventions through its ability to extract inherently hidden features and map it to output in a highly complex multi-dimensional space. Synthesis of electromagnetic (EM) structures with nearly arbitrary with desired functional properties is such an example of a high dimensional optimization space. In this article, we employ deep convolutional neural network (CNN) to allow robust and rapid prediction of scattering properties of nearly arbitrary planar electromagnetic structures on chip. Utilizing this, the work reports an mm-wave PA in 90-nm SiGe with a novel deep learning-enabled inverse design of low-loss, broadband output matching network that achieves a PAE of 16%–24.7%, a saturation power of 16.7–19.5 dBm across Psat, 3 dB bandwidth of 30–94 GHz (103.2%), while supporting both single-carrier high-speed modulation and concurrent multiband multi-Gb/s non-constant amplitude modulation. The Psat, 3 dB bandwidth covers from 5G band up to W-band and is higher than all reported mm-wave silicon PAs which have peak PAE > 20% and demonstrates for the first time concurrent multiband (triple-band) transmission with superior performance at multi-Gb/s. [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 planar multi-circular loop antenna with a wide impedance bandwidth for next generation mm-wave systems. The proposed antenna comprises three circular rings with a partial ground plane with a square slot. The resonating structure is designed on a 0.254 mm thin RO5880 substrate with a relative permittivity of 2.3. The single element of the proposed design showed a resonance response from 26.5 to 41 GHz, with a peak gain of 4 dBi and radiation efficiency of 96%. The proposed multicircular ring antenna element is transformed into a four-element array system. The array size is kept at 18.25 × 12.5 × 0.254 mm3 with a peak gain of 11 dBi. The antenna array is fabricated and measured using the in-house facility. The simulated and measured results are well agreed upon and are found to be suitable for mm-wave communication systems. [ABSTRACT FROM AUTHOR]

A phased-array fed reflector antenna system is presented which can be used for mm-wave base station applications. The proposed system is designed to support massive-multi-input–multi-output (MIMO) scenarios within a wide coverage ($\pm 30^\circ $) in the azimuth plane and a limited coverage at the elevation plane. A design and characterization methodology has been established to optimize the system for the operation in various line-of-sight conditions by adopting the maximum-ratio-transmission (MRT) and zero-forcing (ZF) MIMO algorithms. A two-user MIMO case study has been considered for the evaluation of the key system performance metrics, i.e., the effective isotropic radiated power, power consumption, signal-to-noise-ratio (SNR), and signal-to-interference-plus-noise-ratio (SINR). This study demonstrates that the phased-array fed reflector concept has a major advantage over traditional direct-radiating phased-array (DRPA) antennas to reduce energy consumption. In the present example, it requires 12–14 dB less transmitted power as compared with the MRT-beamformed DRPAs for the same SNR, and 26–27 dB less transmitted power relatively to ZF-beamformed DRPA systems for the same SINR. A prototype, employing a 55 cm diameter torus reflector and operating at 28 GHz-band, has been manufactured and tested. The measurement results agree well with simulations. [ABSTRACT FROM AUTHOR]

In this letter, we have explored the DC, small and large-signal RF reliability of the Power Amplifier (PA) cell for mm-wave applications under DC and RF stress. The PA cell comprises of a single transistor that employs 45RFSOI technology. For the first time here, a PA cell consisting of p-channel partially depleted Silicon-On-Insulator (PD-SOI) FET has been investigated for large-signal reliability behavior. At the same stress conditions, the impact of hot carrier degradation (HCD) on a p-channel FET (PFET) PA cell is also compared with the n-channel FET (NFET) PA cell. As the reliability of the PFET PA cell is superior than NFETs, a deeper investigation of hot carrier degradation and its impact on PA cell reliability is carried out. The PA cell is subjected to extensive RF characterization for varying DC stress and RF power at the gate terminal. The behavior of the time slope exponent of the PFET PA cell is studied to understand the nature of defects. Accelerated aging experiments using DC bias at drain/gate terminals and RF power at the gate terminal is performed. These results show that the RF reliability of the PFET PA cell is superior than its counterpart NFET PA cell at mm-wave frequencies. [ABSTRACT FROM AUTHOR]

The field of Telecommunication has progressed and emerged to be a successful field of technology. From communicating via pigeons and cannonballs to video conferencing for a meeting, the communication has improved surpassing every user's expectation. With the introduction of wireless communication, the field of communication took a different turn. Just when we thought we reached the zenith of wireless communication, an esoteric concept of Standalone (S.A.) and Non-Standalone (N.S.A.) opened the gates to more efficient communication, expanding the horizons of technology. The 5G network has started developing over some regions in the world but the real question remains; which is, whether an efficient communication is worth the economy spent on developing it or certain advantages of this networks should be given up to protect the country's economy. 3rd Generation Partnership Project (3GPP) introduces mainly two network architectures for the deployment of 5G cellular systems over existing LTE networks: Non-Standalone (NSA) and Standalone (SA). NSA permits a quick 5G advantage course of action with the least speculation by leveraging the LTE frameworks which has already been established by cellular Radio Access Technology (RAT), i.e. it follows full 5G protocols and works within the 5G New Radio (NR). This analytical paper elaborates on the performance of these two architectures for the implementation of 5G cellular technology, where the first one would be a high technology-centric approach with less cost effi- ciency and the other one would be the economy savvy aspect with a little bit of negotiation with technology upgrades. [ABSTRACT FROM AUTHOR]

This research work presents the analysis, design, and characterization of a concept for an mm-wave divide-by-4 frequency divider utilizing an extended true single-phase clock (E-TSPC) and a TSPC divide-by-2 stage. The divider operates from 16 to 70 GHz from a 0.8-V supply with the highest power consumption of 0.35 mW. Operating frequencies up to 53 GHz were reached with a supply voltage of only 0.5 V at 0.12-mW power consumption. The self-resonance frequency of the circuit is adjustable through backgate biasing from 40 up to 70 GHz at 0.9-V supply, allowing a reduction in the required input power in this frequency range. Locking ranges up to 114% have been measured by changing only the backgate voltage. The circuit design is illustrated in detail and supported with original analysis and an explicit expression to calculate the self-oscillation frequency of the E-TSPC divider. The presented circuit was fabricated on a 22-nm fully depleted silicon-on-isolator complementary metal–oxide–semiconductor (CMOS) technology and occupies an active area of $3.4 ~\mu \text{m}^{2}$. The circuit requires the lowest power consumption and area among state-of-the-art RF frequency dividers, while it demonstrates the second widest adjustable operating frequency range and the second highest self-resonance frequency for CMOS D-flip-flop frequency dividers. [ABSTRACT FROM AUTHOR]

Phased arrays, commonly used in IEEE 802.11ad and 5G radios, are capable of focusing radio frequency signals in a specific direction or a spatial region. Beamforming achieves such directional or spatial concentration of signals and enables phased array-based radios to achieve high data rates. Designing beams for millimeter wave and terahertz communication using massive phased arrays, however, is challenging due to hardware constraints and the wide bandwidth in these systems. For example, beams which are optimal at the center frequency may perform poor in wideband communication systems where the radio frequencies differ substantially from the center frequency. The poor performance in such systems is due to differences in the optimal beamformers corresponding to distinct radio frequencies within the wide bandwidth. Such a mismatch leads to a misfocus effect in near-field systems and the beam squint effect in far-field systems. In this paper, we investigate the misfocus effect and propose InFocus, a low complexity technique to construct beams that are well suited for massive wideband phased arrays. The beams are constructed using a carefully designed frequency modulated waveform in the spatial dimension. InFocus mitigates beam misfocus and beam squint when applied to near-field and far-field systems. [ABSTRACT FROM AUTHOR]

This paper presents a compact 213 GHz fundamental oscillator with an optimal embedding network that maximizes the output power. Fabricated in 65-nm bulk CMOS, the oscillator occupies a core area of only 70×40 pm2, owing to the use of a compact low-loss capacitive transformer structure. The oscillator achieves 0.56-mW output power while consuming a DC current of 14.35 mA from a 1-V power supply, representing a recording-breaking DC-to-RF efficiency of 3.9% amongst fundamental oscillators above 200 GHz.

This paper presents challenges and design perspectives for terahertz (THz) integrated circuits and systems. THz means different things to different people. From International Telecommunication Union (ITU) perspective, THz radiation primarily means frequency range from 300 – 3000 GHz. However, recently, a more expansive definition of THz has emerged that covers frequencies from 100 GHz to 10 THz, which includes sub-THz (100 – 300 GHz), ITU-defined THz frequencies. This definition is now commonly used by communication theorists, and since this paper is intended for people with a wide variety of expertise in system and circuit design, we have adopted the latter definition. The paper brings to the open unmitigated shortcomings of conventional transceiver architectures for multi gigabit-per-second wireless applications, unfolds challenges in designing THz transceivers, and provides pathways to address these impediments. Furthermore, it goes through design challenges and candidate solutions for key circuit blocks of a transceiver including front-end amplifiers, local oscillator (LO) circuit and LO distribution network, and antennas intended for frequencies above 100 GHz.

The AlN/GaN/AlN heterostructure is attractive for microwave and millimeter-wave power devices due to its thin top barrier, tight carrier confinement, and improved breakdown voltage. This work explores the large-signal RF performance of high-electron-mobility transistors on this heterostructure. Results are highlighted by record high on-current of 3.6 A/mm, and record maximum oscillation frequency ( $f_{max}$ ) of 233 GHz. The load-pull power sweep at 10 GHz demonstrate a peak power added efficiency (PAE) of 22.7% with an associated gain ( $G_{T}$ ) of 8.7 dB and output power ( $P_{out}$ ) of 3 W/mm. When optimized for power, the peak $P_{out}$ of 3.3 W/mm has an associated PAE of 14.7% and $G_{T}$ of 3.2 dB. This first demonstration is encouraging for the mm-wave power potential of the AlN/GaN/AlN HEMT.

Accurate prediction of the large-scale channel fading is fundamental to planning and optimization in 5G millimeter-wave cellular networks. The current prediction methods, which are either too computationally expensive or inaccurate, are unsuitable for city-scale cell planning and optimization. This paper presents FadeNet, a convolutional neural-network enabled alternative for predicting large-scale fading with high computation speed and accuracy. By using carefully designed input features and neural-network architecture to capture topographical information, FadeNet accurately predicts the large-scale fading from a base station to each location in its coverage area. Evaluations on realistic data, derived from millimeter-wave cells across multiple cities, suggest that FadeNet can achieve a prediction accuracy of 5.6 decibels in root mean square error. In addition, by leveraging the parallel processing capabilities of a graphics processing unit, FadeNet can reduce the prediction time by 40X - 1000X in comparison to industry prevalent methods like ray-tracing. Generalizations of FadeNet, that can handle variable topographies and base station heights, and its use for optimal cell site selection are also explored.

Recent standardization of portions of the millimeter-wave (mm-wave) band for fifth-generation (5G) operation has called for further research on how short-term fading behaves in that unexplored part of the spectrum. With such a target, this paper reports on a thorough measurement campaign conducted in an indoor environment characterized by rich-multipath scattering, a part of a modern building, with floor and ceiling constructed of reinforced concrete over steel plates with wood and plasterboard-paneled walls. Particularly, measurements have been performed in a variety of scenarios, under line-of-sight (LoS) and non-line-of-sight (nLoS) conditions, for a wide range of frequencies, namely from 25 to 40 GHz- a span of 15 GHz- therefore, including 26, 28 and 39 GHz. First and second order statistics of representative fading models, namely Rayleigh, Rice, Nakagami, folded normal, ${\alpha } $ - ${\mu } $ , ${\eta } $ - ${\mu }$ , ${\kappa } $ - ${\mu } $ , and ${\alpha } $ - ${\eta } $ - ${\kappa } $ - ${\mu } $ have been investigated. The metrics used in the analysis were the normalized mean square error (NMSE), the Kolmogorov-Smirnov (KS), and the Akaike information criterion (AIC). Additionally, the study of the ${\kappa } $ - ${\mu } $ model is advanced, in which new, exact, simple closed-form expressions for probability density function, cumulative distribution function, and level crossing rate are derived for some particular cases, namely for ${\mu = n+ 1/2}$ in which ${n\in {{\mathbb {N}}}}$ .

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.

The millimeter-wave (mm-wave) band is expected to be the optimal solution for future wireless communication systems as it provides a wide bandwidth, which enhancing data transmission rate. Therefore, high-directive antennas, principal elements for mm-wave wireless communications, are used at the mm-wave band as they can overcome the negative effect of high path losses. A transmit-array antenna (TA) operates at the mm-wave band (around 28 GHz) with high aperture efficiency, high gain, wide bandwidth, and low-profile TA surface has been designed. Basically, the aperture efficiency of the TA depends on the unit cell (UC) characteristics, and feed antenna radiation pattern. Therefore, the UC elements designed based on capacitive differential feeding and true time delay techniques, as a result the designed UC has a wide bandwidth with a stable broadside radiation pattern, high cross-polarization discrimination and a full phase range (0–360°) and a maximum element loss of 0.5 dB. Moreover, the designed UC rotates the polarization of linearly polarized electromagnetic (EM) wave to its orthogonal direction with high efficiency, a polarization conversion ratio higher than 0.9 is achieved within the operating frequency band. The used techniques to design the proposed UC have a significant effect on TA antenna performance, in terms of gain and bandwidth. The TA antenna surface and the feeding antenna have been designed and fabricated. The maximum gain is 31.15 dBi. The 1 dB gain bandwidth is 12.7% while the 3 dB gain bandwidth is 21% around 28 GHz. The aperture efficiency is better than 50% and the cross-polarization level is less than −37 dB, on the frequency range from 25 to 31.5 GHz.

The integration of sub-6-GHz and millimeter-wave (mm-wave) bands has become an important issue for future fifth generation (5G) wireless communications owing to their large frequency ratios. This paper proposes a compact-size dual-function antenna operating at 3.5 GHz and the mm-wave band (28 GHz) for 5G mobile applications using a frequency reconfigurability technique. The proposed antenna comprises a microstrip patch linked with a meandered radiating structure through a radio frequency PIN diode to achieve frequency reconfigurability between the two bands. A significant size reduction up to 15.3 mm × 7.2 mm × 0.508 mm for the proposed antenna was achieved using a meandered line structure and truncated ground plane. To enhance the functionality, 8 × 8 multiple-input multiple-output (MIMO) with possible long- and short-edge antenna placement configurations were demonstrated. The system exhibited satisfactory MIMO characteristics with wide decoupling -10 dB bandwidths of 7.4% and 4.8% at the low- and high-frequency bands, respectively, without utilizing any external decoupling structure. The simulated results were validated using fabricated prototypes, and good agreement was observed. Additionally, a safety analysis based on the specific absorption rate and power density at the prescribed frequency bands was conducted using a realistic human model, and the results were found to be in accordance with the safety guidelines. Owing to the integration of sub-6-GHz and mm-wave bands in a single compact structure with a large frequency ratio and good MIMO performance, the proposed antenna system is suitable for future 5G mobile handheld devices.

This paper presents a transmitter (TX) and a receiver (RX) with bowtie-antenna and silicon lens for gas spectroscopy at 222-270 GHz, which are fabricated in IHP’s $0.13~\mu \text{m}$ SiGe BiCMOS technology. The TX and RX use two integrated local oscillators for 222 – 256 GHz and 250 – 270 GHz, which are switched for dual-band operation. Due to its directivity of about 27 dBi, the single integrated bowtie-antenna with silicon lens enables an EIRP of about 25 dBm for the TX, and therefore a considerably higher EIRP for the 2-band TX compared to previously reported systems. The double sideband noise temperature of the RX is 20,000 K (18.5 dB noise figure) as measured by the Y-factor method. Absorption spectroscopy of gaseous methanol is used as a measure for the performance of the gas spectroscopy system with TX- and RX-modules.

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.