GHz Band Research Articles

A coding based metasurface absorber with triple circular ring resonator for broadband RCS reduction and high EMI shielding effectiveness

In this paper, a novel coding-based metasurface absorber (CMA) featuring a triple circular ring resonator is introduced for broadband radar cross-section (RCS) reduction and high electromagnetic interference (EMI) shielding effectiveness. The coding element comprises a triple circular ring resonator generating a 1-bit coding scheme (‘0’ and ‘1’ element) with a reflection phase difference of 180° ± 45° across the frequency range of 7.5 GHz–15.5 GHz by employing varying dimensions for the outer circular ring. A most affordable FR-4 substrate with 1.6 mm thickness is used to design the CMA structure. Binary Particle Swarm Optimization (BPSO) algorithm combined with array theory is employed to strategically position unit cells within the subarray. Simulations demonstrate a significant RCS reduction of −10 dBsm across the entire 7.5 GHz–15.5 GHz band. Furthermore, the 2D and 3D scattering patterns observed at 8.26 GHz, 10.56 GHz, and 13.30 GHz serve as additional proof of the remarkable effectiveness of the optimized pattern in reducing bi-static RCS. The optimized CMA structure also exhibits absorption levels exceeding 80 % at different resonance frequency while maintaining high shielding effectiveness. To validate these findings, a prototype of the optimized CMA structure is fabricated, and experimental investigations are conducted. The measured results closely align with the simulated outcomes, with minor discrepancies observed outside the designated frequency band. Based on comprehensive simulation and experimental analyses, the optimized CMA structure emerges as a promising choice for achieving broadband RCS reduction and high EMI shielding effectiveness in practical applications.

Omniscatte: Extreme Sensitivity MMWave Backscattering Using Commodity FMCW Radar

With the Internet of Things (IoT) anticipated to grow up to a trillion devices by 2035 [1] and 6G aiming at 10/m2 Massive Machine Type Communications [2], massive connectivity has long been considered a key to the success of IoT and diverse emerging services. Backscatter is an attractive option for scalability, operating at tens of µW [3] by reflecting the wireless signal without generating the power-hungry passband signal itself. The ultra-low power operation of backscatter offers long-term sustainability. In particular, recent advances in mmWave backscatters [4,5,6] present a great potential for scalability by exploiting the abundant spectrum resource in the mmWave ranging up to 14 GHz (60 GHz band); a bandwidth over two orders of magnitude greater than 26 MHz and 100 MHz in the popular 900 MHz and 2.4 GHz bands, respectively.

Unveiling the Impact: Human Exposure to Non-Ionizing Radiation in the Millimeter-Wave Band of Sixth-Generation Wireless Networks

The investigation into potential hazards linked with millimeter-wave (mmWave) radiation is crucial, given the widespread adoption of body-centric wireless sensor nodes operating within this frequency band. This is particularly pertinent in light of its envisaged use for the upcoming 5G/6G networks and beyond. As 6G is anticipated to leverage a broad spectrum, including both sub-6 GHz and mmWave bands (30–300 GHz), concerns arise regarding increased human exposure to non-ionizing radiation (NIR). This work highlights the advantages of deploying 6G in the mmWave band, focusing on evaluating human body exposure to NIR interactions. Additionally, this research aims to address mmWave NIR exposure by introducing a Distributed Base Station (DBS) network. Utilizing low-power remote antennas to extend network coverage, the DBS architecture seeks to effectively minimize NIR’s impact without compromising overall network performance. The findings underscore the significant potential of the DBS approach in mitigating NIR-related concerns associated with mmWave utilization in 6G networks.

A Review of mm-wave Antenna Design at 60 GHz for 5G Applications System

The rapid advancement of mobile technology is closely tied to developments in electronic circuit designs and computer science. As a result, it is important to monitor the progress of antenna systems, which form the foundation of wireless technology. Microstrip patch antennas have emerged as a leading design in modern communication methods due to their small size, low cost, and ease of manufacturing. Over the past 40 years, numerous studies have been conducted on antenna systems, and this review article provides a comprehensive overview of the earlier and more recent achievements in microstrip patch antennas in the 60 GHz band, which is a crucial frequency range for fifth-generation (5G) technologies. This article discusses mm-wave antennas operating at 60 GHz and provides brief descriptions of their properties, construction techniques, and some related difficulties.

Dual-band 5G MIMO antenna with enhanced coupling reduction using metamaterials

This article introduces a miniaturized dual-band multiple input multiple output (MIMO) antenna with wide bandwidth and high isolation. The design incorporates ground plane modifications and utilizes metamaterials to achieve dual-band operation in the millimeter wave spectrum for 5G applications, specifically operating at the 28/38 GHz frequency bands. The proposed antenna maintains its dual-band functionality despite its compact size of 3.8 times 3.7 times 0.787 text {mm}^3 (without the feed line). The antenna is fabricated on a Rogers RT5880 substrate with a thickness of 0.787 mm and with relative permittivity varepsilon _r = 2.2. The MIMO system comprises two symmetric radiating elements positioned in close proximity, resulting in mutual coupling levels of - 20 dB and - 12 dB at 25 GHz and 37 GHz, respectively. Modifications are made to the ground length to enhance the isolation at the higher frequency band while embedding metamaterials effectively reduces the coupling at the lower frequency band. The incorporation of metamaterials leads to an enhanced bandwidth from 3.8 to 4.8 GHz in the desired lower band (24–28.8 GHz) and from 3.8 to 4.2 GHz in the higher band (36.6–40.8 GHz). The proposed system can operate across the 28/38 GHz bands using a compact design, thus offering reasonable isolation, an envelope correlation coefficient below 0.0001, and a significant diversity gain (> 9.99 dB). These attributes emphasize the system’s suitability for 5G millimeter-wave cellular communications.

DEFECTED GROUND SQUARE PATCH EDGE TRUNCATED POLARIZATION RECONFIGURABLE ANTENNA

In this paper, a polarization reconfigurable antenna is reported. The proposed antenna operates in linear and circular polarization. Linear polarization is obtained using a square patch antenna and circular polarization is realized by truncating the diagonal corners of the square patch. Wideband circular polarization is obtained using two triangular defects to the ground plane beneath the truncated edge. To implement polarization reconfigurability, two pin diodes are placed on the truncated edges. These pin diodes electronically transform the proposed structure into square or truncated square patches resulting in linear or circular polarizations respectively. The proposed antenna operates in the 4.75 to 3 GHz band with circular polarization and the 4.75 to 1 GHz band with linear polarization. The antenna exhibits a higher peak gain of 7.7 dBi due to a low-loss foam substrate with the main lobe at 0°. A prototype of the antenna is developed and tested.

TRIPLE-BAND CIRCULAR PATCH MICROSTRIP ANTENNA FOR WIRELESS COMMUNICATION

In this article, a triple-band patch antenna using a circular patch microstrip antenna is constructed with a low-profile patch antenna using a 1.5 mm thick FR4 substrate (εr= 4.3). As mobile devices like smartphones and laptops become more common, the usage of tiny, triple-band antennas has also become more common. The objective of this research is to design a circular patch antenna with a 3–11 GHz dipole-like radiation pattern, which may be used for industrial, scientific, and medical reasons. For the suggested triple-band antenna design, the slotted radiator with six arches and the reduction of the ground plane are among the components. In addition, the standard 50 Ω RF transmission line stimulates the patch antenna; this transmission line is attached to the microstrip line by an impedance-compliant SMA connection. Data from the experiments are obtained, evaluated, and compared; to the patch's surface current distributions, gain, and radiation patterns. According to the measurements, S11 has an impedance bandwidth in the 5.5 GHz band of less than -10 dB, 6.6 GHz band, and 10.4 GHz band at all frequencies. The superb radiation pattern performance, relatively consistent gain throughout the bands, and practical bandwidths of this antenna make it a good choice for C-band and dual X-band applications.

Measurement-Based Characterization of Subterahertz Metasurfaces Designed to Work in a 300-GHz Band: Suitability for broader band communication in 6G

Measurement-Based Characterization of Subterahertz Metasurfaces Designed to Work in a 300-GHz Band: Suitability for broader band communication in 6G

How does Wi-Fi 6 fare? An industrial outdoor robotic scenario

Wi-Fi is a standard off-the-shelf solution for industrial robotics. The IEEE 802.11ax amendment extends it to support the 6 GHz band, 160 MHz bandwidth and bit-rates up to 9.6 Gbps. In this article, we evaluate the performance of Wi-Fi 6 compared to Wi-Fi 5 and Wi-Fi 4. We select 9 physical layers (PHYs) representing different Wi-Fi generations and we evaluate their performance in an industrial shipyard in the presence of high radio frequency interference and metallic obstructions. We deploy setup of a robotic station (STA) and a controller STA with three applications running in parallel: a robotic STA is sending a high throughput stream to a controller, a Robotic Operating System (ROS) application is sending time-critical control commands to the robotic STA, Precision Time Protocol (PTP) keeps synchronizing the clocks between both STAs. We evaluate the performance in terms of three Key Performance Indicators (KPIs): streaming throughput, IP-level delay using PTP, and Application-level delay of ROS control packets. The networks are run in: Short range Line of Sight (LoS), Medium range LoS, Long range None-LoS (NLoS), and Long range mixed settings. We note that depending on the PHY configuration, an older Wi-Fi generation may outperform Wi-Fi 6. We further observe trade-offs between the different PHYs: wide channel PHYs (e.g. 160 MHz) had best throughput reaching up to 900 Mbps while PHYs while 80 MHz or 20 MHz bandwidth achieved as low as 9 ms delay. This motivates further research in multi-PHY adaptation for KPIs specific to industrial robotics.

6G Vision, IoT Technologies, Challenges and Emerging Technology Solutions—A Survey

The fifth generation (5G) is yet to be implemented globally, researchers have been impelled to envision 6G to provide evolving services and applications with high-class execution. The sixth-generation network technology is expected to support huge number of Internet of Things (IoT) devices needed to sustain higher data rates applications. Compared to the IoT provisions deployed in 5G, 6G IoT uses high density diverse gadgets with huge bandwidth, robust architecture and smart algorithms built on artificial intelligence (AI). It will enable novel applications with the help of AI and big data technologies. The existing 6GHz band is at present packed by data traffic. The lower transmission band cannot withstand higher data traffic transmission. Communication technology based on the Millimeter Wave (mmWave) is capable of supporting higher data rate transmission but at the cost of consuming high power and high hardware cost, thus violating the low-cost design norm of IoT devices. In this paper, we aim to provide 6G vision of IoT, the Key technologies and challenges involved. Various approaches such as Radio over Fiber technologies, wireless beam modulation (WBM) technique for transmitting mmWave, Satellite communication system is anticipated to perform a major role in IoT and applications in 6G vision and green communication for super performance in terms of energy efficiency are addressed to meet the high requirements of a 6G IoT system. Techniques such as convergence of 6G IoT with RoF will provide benefits of both wireless and optical technology, generating more challenges and prospects in the future. A comprehensive survey of current developments in 5G and 6G and future trends is presented in this survey article.

A 24−30 GHz 8-element dual-polarized 5G FR2 phased-array transceiver IC with 20.8-dBm TX OP1dB and 4.1-dB RX NFin 65-nm CMOS

This article presents an 8-element dual-polarized phased-array transceiver (TRX) front-end IC for millimeter-wave (mm-Wave) 5G new radio (NR). Power enhancement technologies for power amplifiers (PA) in mm-Wave 5G phased-array TRX are discussed. A four-stage wideband high-power class-AB PA with distributed-active-transformer (DAT) power combining and multi-stage second-harmonic traps is proposed, ensuring the mitigated amplitude-to-phase (AM-PM) distortions across wide carrier frequencies without degrading transmitting (TX) power, gain and efficiency. TX and receiving (RX) switching is achieved by a matching network co-designed on-chip T/R switch. In each TRX element, 6-bit 360° phase shifting and 6-bit 31.5-dB gain tuning are respectively achieved by the digital-controlled vector-modulated phase shifter (VMPS) and differential attenuator (ATT). Fabricated in 65-nm bulk complementary metal oxide semiconductor (CMOS), the proposed TRX demonstrates the measured peak TX/RX gains of 25.5/21.3 dB, covering the 24−29.5 GHz band. The measured peak TX OP1dB and power-added efficiency (PAE) are 20.8 dBm and 21.1%, respectively. The measured minimum RX NF is 4.1 dB. The TRX achieves an output power of 11.0−12.4 dBm and error vector magnitude (EVM) of 5% with 400-MHz 5G NR FR2 OFDM 64-QAM signals across 24−29.5 GHz, covering 3GPP 5G NR FR2 operating bands of n257, n258, and n261.

Switchable and optically transparent ultrawide stopband frequency selective surface for electromagnetic shielding

In view of the fact that high-frequency electromagnetic waves mainly enter buildings through windows and glass doors, switchable optically-transparent shielding with broad stopband is increasingly needed. Herein, a novel design for a switchable and optically transparent frequency selective surface (FSS) with ultrawide-stopband is presented in this study. The structure consists of a polymethyl methacrylate (PMMA) layer sandwiched between polydimethylsiloxane (PDMS) layers which contain liquid metal microchannels arranged in an orthogonal Ω-shaped configuration. The mobility of the liquid metal can switch the FSS response from an all-pass to an ultrawide bandstop behavior. The proposed FSS achieves a rejection bandwidth of 18.1 GHz, covering P, L, S, C, X and Ku bands, while maintaining a transparency of 81% and high angular stability up to 80°, regardless of polarization. Furthermore, the mechanism behind the ultrawide stopband and high angular stability is explored through an analysis of reflection and absorption for both TE polarization and TM polarization. Experimental validation under both normal and oblique incidence demonstrates the ultrawide-stopband performance of the fabricated FSS.

Recent Trends in Compact Planar Antennas at 5G Sub-6 GHz and mmWave Frequency Bands for Automotive Wireless Applications: A Review

Recent Trends in Compact Planar Antennas at 5G Sub-6 GHz and mmWave Frequency Bands for Automotive Wireless Applications: A Review

High Output Power and Efficiency 300-GHz Band InP-Based MOS-HEMT Power Amplifiers With Composite-Channel and Double-Side Doping

High Output Power and Efficiency 300-GHz Band InP-Based MOS-HEMT Power Amplifiers With Composite-Channel and Double-Side Doping

Low-noise integrated balanced-mixer for 300-GHz band based on Fermi-level managed barrier diode on Si platform

Low-noise integrated balanced-mixer for 300-GHz band based on Fermi-level managed barrier diode on Si platform

An E‐band 3D‐printed dielectric lens antenna with flat‐top beam designed by hybrid optimization algorithm

AbstractAn all‐dielectric lens antenna (LA), with flat‐top radiation patterns in both E‐ and H‐planes, is proposed. The antenna covers the 64–70 GHz band. The dielectric LA consists of a source horn (LB‐12‐15‐A with WR12) and a dielectric lens. The lens is composed of multiple layers of dielectric rings with different heights. The structural parameters of the dielectric lens are optimized by a hybrid optimization algorithm (particle swarm optimization [PSO]‐genetic algorithm [GA]) that involves genetic operations of GA and PSO. The hybrid algorithm is beneficial to enhance the optimization efficiency, and an objective function is designed to optimize the beam width, the S11, and the sidelobe level (SLL). Both the simulated and measured results show that the dielectric LA provides good flat‐top radiation patterns within the desired band. Moreover, the dielectric lens is manufactured by three‐dimensional‐printed technology, which allows for low cost, easy manufacturing, and lightweight.

Optimization and Performance of Metamaterial- Based Electromagnetic Scattering Sheet for Coverage Improvement in 28 GHz Band

Optimization and Performance of Metamaterial- Based Electromagnetic Scattering Sheet for Coverage Improvement in 28 GHz Band

Using generative model for intelligent design of dielectric resonator antennas

AbstractIn the advancing field of 5G technologies, particularly at the 60 GHz band, dielectric resonator antennas (DRAs) stand out for their low conduction loss and high radiation efficiency. However, the traditional design process for DRAs, predominantly reliant on intuitive reasoning and trial‐and‐error methods, is notably inefficient and resource‐intensive. Addressing this critical challenge, our research introduces a pioneering approach: a generative adversarial network (GAN)‐based model specifically tailored for automating DRA structure design. This novel model represents the first of its kind in the domain, marking a significant departure from conventional methods. Our GAN model uniquely integrates a simulator for DRA modeling and a generator for DRA structure design, streamlining the design process. To effectively train this model, we created a simulated data set comprising pattern–annotation pairs of geometric shapes and S11 parameters. This data set enabled the GAN to capture the intrinsic principles underlying DRA design. The practical impact of our model is profound; it significantly expedites the DRA design process, aligning it more closely with specific user requirements while conserving valuable time and resources. This breakthrough approach not only enhances the efficiency of DRA design but also sets a new standard in antenna technology development for future wireless communications.

Blockage loss and shadow fading behavior of millimeter‐wave signals due to human bodies at 28 GHz

AbstractAs the millimeter‐wave (mm‐Wave) spectrum is considered to be an essential enabler to the fifth generation (5G) wireless communication systems. Human movements are one of the most significant factors that cause transient blockage in indoor mm‐wave channels. In this letter, human blockage measurements and shadow fading statistics due to human body movements in an indoor office environment are reported for the 28 GHz band. The effect of human bodies on the channel is measured for several scenarios including a variety of population and using diverse antenna heights. The reported shadow fading statistics include both the duration and the depth of the blockage fade, and accordingly, we propose several empirical models that cater for such blockage events. The findings reported in this letter could improve the modeling of indoor radio channels at 28 GHz bands by considering the presence of humans, as well as their movements.

Development of Measurement Phantom for Absorbed Power Density Assessment by Human Exposure at 28 GHz Band

Development of Measurement Phantom for Absorbed Power Density Assessment by Human Exposure at 28 GHz Band