Ultra-wideband Research Articles

A Gaussian Process-Enhanced Non-Linear Function and Bayesian Convolution–Bayesian Long Term Short Memory Based Ultra-Wideband Range Error Mitigation Method for Line of Sight and Non-Line of Sight Scenarios

Relative positioning accuracy between two devices is dependent on the precise range measurements. Ultra-wideband (UWB) technology is one of the popular and widely used technologies to achieve centimeter-level accuracy in range measurement. Nevertheless, harsh indoor environments, multipath issues, reflections, and bias due to antenna delay degrade the range measurement performance in line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. This article proposes an efficient and robust method to mitigate range measurement error in LOS and NLOS conditions by combining the latest artificial intelligence technology. A GP-enhanced non-linear function is proposed to mitigate the range bias in LOS scenarios. Moreover, NLOS identification based on the sliding window and Bayesian Conv-BLSTM method is utilized to mitigate range error due to the non-line-of-sight conditions. A novel spatial–temporal attention module is proposed to improve the performance of the proposed model. The epistemic and aleatoric uncertainty estimation method is also introduced to determine the robustness of the proposed model for environment variance. Furthermore, moving average and min-max removing methods are utilized to minimize the standard deviation in the range measurements in both scenarios. Extensive experimentation with different settings and configurations has proven the effectiveness of our methodology and demonstrated the feasibility of our robust UWB range error mitigation for LOS and NLOS scenarios.

Mathematical modeling development and synthesis of tapered transmission line resonators and filters

Abstract Tapered transmission line resonators can be used to achieve specific frequency responses and enhance the performance of microwave devices and impedance transformers. To develop a mathematical model (transfer function) of such a wideband resonator will facilitate the construction of an equivalent circuit and the synthesis of resonators of this type. This study discusses the system modeling of tapered transmission line (TTL) resonators using the singularity expansion method (SEM). The transfer function is analytically established for two types of wideband TTL resonators: exponential tapered transmission lines (ETTL) and linear tapered transmission lines (LTTL). The analytical transfer function is derived for the general tapered ratio (k/β). The physical poles of the structures are identified using the pole-energy matrix pencil (MP) approach. The transfer function expression is then utilized to develop an accurate equivalent lumped-element circuit for the TTL resonator. This study’s simplified approach for estimating the transfer function and associated poles and zeros from the S-parameters is the main contribution, whereas it is known that the transfer function becomes complicated for wideband frequency response. A direct synthesis approach is presented to develop two-stage and four-stage ultra-wideband (UWB) bandpass filters. The agreement between the frequency response data and the derived transfer function of the system model of the synthesized TTL filters demonstrates the reliability of the presented method. The proposed system modeling and synthesis methodology can be applied to more sophisticated filter TTL architectures.

A dual-port MIMO antenna with integrated band-reject filter for 5G sub-6 GHz/FR1 applications

Abstract This study presents the design and realization of a dual-port multiple-input–multiple-output (MIMO) filtering antenna system. The device shows good response in the frequency rage 1 (4.1 to 7.125 GHZ) frequency band, which handles most of the cellular mobile communication traffic. First, the single element ultra-wideband (UWB) filtenna is designed by combining a UWB antenna and a band-reject filter (BRF) where the antenna works in the frequency range from 1 to 11 GHz and the BRF is rejecting the frequency range of 3–3.42 GHz with 3.2 GHz as its resonant frequency. Finally, the proposed two-port MIMO filtenna combines two single element UWB filtennas in antiparallel manner which shows impedance bandwidth from 2.59 to 7.1 GHz with a band notch from 3 to 3.42 GHz. The structure is built on cost-efficient FR4 substrate (εr = 4.4, tanδ = 0.02) of dimensions 0.68 ${{\boldsymbol{\lambda }}_{\boldsymbol{c}}}$ ×0.27 ${{\boldsymbol{\lambda }}_{\boldsymbol{c}}}$ ×0.01 ${{\boldsymbol{\lambda }}_{\boldsymbol{c}}}$ (mm3), which is compact in size and utilizes a defected ground structure for further miniaturization. The proposed design is simulated using Ansys HFSS software, and after fabrication, it is measured, and the output shows good results for the proposed application. The designed antenna system is suitable for fifth-generation (5G) wideband systems.

Indoor Positioning Systems in Logistics: A Review

Background: Indoor Positioning Systems (IPS) have gained increasing relevance in logistics, offering solutions for safety enhancement, intralogistics management, and material flow control across various environments such as industrial facilities, offices, hospitals, and supermarkets. This study aims to evaluate IPS technologies’ performance and applicability to guide practitioners in selecting systems suited to specific contexts. Methods: The study systematically reviews key IPS technologies, positioning methods, data types, filtering methods, and hybrid technologies, alongside real-world examples of IPS applications in various testing environments. Results: Our findings reveal that radio-based technologies, such as Radio Frequency Identification (RFID), Ultra-wideband (UWB), Wi-Fi, and Bluetooth (BLE), are the most commonly used, with UWB offering the highest accuracy in industrial settings. Geometric methods, particularly multilateration, proved to be the most effective for positioning and are supported by advanced filtering techniques like the Extended Kalman Filter and machine learning models such as Convolutional Neural Networks. Overall, hybrid approaches that integrate multiple technologies demonstrated enhanced accuracy and reliability, effectively mitigating environmental interferences and signal attenuation. Conclusions: The study provides valuable insights for logistics practitioners, emphasizing the importance of selecting IPS technologies suited to specific operational contexts, where precision and reliability are critical to operational success.

Dynamic control, routing, and resource assignment in multi-granular optical node topologies combining wavelength, waveband, and spatial switching for 6G transport networks [Invited

Effective management of end-to-end 6G network services is crucial, with peak capacity requirements for 6G transport connections expected to exceed 1 Tb/s. As demand for high bandwidth rises, there is a growing necessity for high-capacity optical fiber links, including ultra-wideband (UWB) and multiple fiber links within the network. Scaling up to accommodate these demands, designing wavelength-selective switches (WSSs) for such networks significantly increases the port count. To tackle this issue, we propose various multi-granular optical node (MG-ON) architectures utilizing heterogeneous wavelength, waveband, and spatial switching. We evaluate these architectures’ performance against high-capacity wavelength division multiplexed (WDM) networks through various simulation parameters.

INVESTIGATION OF THE EFFECTS OF DIFFERENT FEED LINE STRUCTURES ON UWB ANTENNA PERFORMANCE BY CHARACTERISTIC MODE ANALYSIS

This study investigates the effect of various feed topologies on the parameters of a novel ultra-wideband (UWB) antenna using characteristic mode analysis. The proposed design is guided by characteristic mode analysis, commencing with a basic square structure. Initially, a closed-form estimate of the resonance frequencies of the primary modes is provided for the square-shaped structure. Subsequently, the characteristic modes that resonate in the frequency spectrum are modified by introducing symmetrical square slots. To excite these modes and achieve a wideband antenna that encompasses the relevant spectrum, the geometry of the feeding line is altered and its effects are examined. The study incorporates two fundamental feed line geometries: tapered and traditional feed impedance lines. The proposed UWB antennas are fabricated and measured to validate their performance. According to the measurement results a wide impedance bandwidth of 147.82% at -10 dB reference ((0.9–6 GHz)) and stationary radiation patterns across the operating frequency band are obtained for the tapered feed line. The results demonstrate a significant advantage of the tapered feed line over the traditional impedance line. The results for the fabricated prototypes exhibit high similarity to the simulated results. The findings confirm the applicability of the mode analysis method.

Planar compact four port MIMO antenna for Ultra Wideband applications

This work presents a small four-port multiple-input multiple-output (MIMO) antenna for Ultra Wideband (UWB) applications. Four monopole radiating components make up the suggested antenna. Every monopole is positioned perpendicularly to the components that surround it. This compact antenna, 40 mm × 40 mm, is printed on a single layer substrate (FR4) with a thickness of 1.6 mm and an εr = 4.4. This antenna features an isolation of less than −14 dB and an impedance bandwidth (S11 < −10 dB) of 2.57–12.20 GHz. The average gain is 4.7 dBi and the envelope correction coefficient (ECC) is less than 0.15. The suggested antenna is a good option for UWB applications because of its Ultra Wide bandwidth and small footprint.

Ultra-wide band and high efficient Polarization converting metasurface employing Bell-shaped unit cell for RCS reduction

Polarization is a dominant parameter regarding communication systems in recent times. The standard polarization techniques can be used only to a certain extent because of their huge size and limited bandwidth constraints. A design of bell-shaped polarization converting metasurface (PCMS) is presented in this paper which is highly efficient for Radar cross section (RCS reduction) and also operates in ultra-wideband. The designed PCMS attains a polarization conversion ratio of more than 90% by demonstrating the transformation of the linear polarization wave to its orthogonal counterpart. The PCMS is arranged in a triangular chessboard configuration to reduce the RCS. RCS reduction is obtained by achieving destructive interference, accomplished by two unit cells. The two unit cells, PCMS and its mirror will have a phase difference of 180 ± 37°. The phase cancellation is obtained by rotating and arranging the proposed PCMS at 90°, 180° and 270°. RCS reduction is obtained in a frequency range from 4 GHz to 24.8 GHz with 144% FBW. This PCMS is verified experimentally. A good agreement is found between the simulation and the experimental results.

RT-SVM: Channel modeling and analysis for indoor terahertz communication scenarios

Considering the increasing demands for wireless communication networks and information system applications, the wireless sector must meet the pressing requirement for high-speed technological advances. The terahertz (THz) frequency band, spanning 0.3 to 10 THz, is of significant interest in current technological innovations and academic research in telecommunications. The THz frequency band has unique properties, including high time-resolving power (femtosecond) and low absorption. This paper proposes a THz propagation ultra-wideband (UWB) channel model and coding scheme for indoor environments starting from 0.3 THz. First, we investigated the propagation path loss model by considering the effects of transmitter dimensions, molecular absorption, and attenuation as functions of frequency and distance. We developed models for power propagation delay, multiple input multiple output (MIMO) systems and discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) response channels. Using the standard Saleh-Valenzuela model combined with Ray-tracing (RT-SVM), we studied the transmission of THz signals in indoor scenarios. We introduced physical parameters relevant to the THz indoor channel, such as line-of-sight (LoS) path loss, power distributions, temporal and spatial properties, and associations between THz multipath properties. These parameters were integrated with the RT-SVM channel model and applied to THz indoor communication. Numerical simulations demonstrate that the proposed hybrid channel model enhances THz system performance and outperforms traditional statistical and geometric-based stochastic channel models in terms of temporal and spatial dimensions, contributing to frequency loss variations.

Оксид галію — перспективний мультифункціональний матеріал четвертого покоління (огляд)

This work is devoted to the analysis and systematization of the main information on the properties of gallium oxide and materials based on it and their practical application, as well as the prospects for further research of the specified actual oxide material. A review of literature data concerns general properties and structure of gallium oxide Ga2O3, various methods to produce Ga2O3 thin films, nanostructures, bulk crystals, powders, the application of gallium oxide in various fields of science and technology, including semiconductor field, electronic engineering, optoelectronics, the creation of composite transparent materials, etc. In the last thirty years or so, thanks to the progress in growing large-volume, high-quality gallium oxide crystals, this material with an ultra-wide band gap and a high critical breakdown field has gained significant application in the manufacture of the latest power electronics and high-voltage electronic devices. Important experimental studies, in particular, in terms of developing methods of metallization, joining similar materials, connecting electrical contacts, for example, by soldering, require the study of the wetting of these oxide materials by metal melts and the contact interaction at the interphase boundaries. Data on surface phenomena, in particular the wetting of gallium oxide by metals, are practically absent in the literature, and this requires further additional research. Keywords: gallium oxide, physical properties, semiconductor, power electronics, optoelectronics, transparent composite materials.

Design and Optimization of a Half-Circular Ultra-Wideband Patch Antenna Using Genetic Algorithm

This research introduces an optimization design of an ultra-wideband (UWB) half-circular planar antenna using genetic algorithm. The optimization process is conducted using an Application Programming Interface (API) links two softwares; MATLAB environment and ANSYS HFSS software. The UWB antenna design includes a semi-circular patch element, the UWB behavior is obtained using truncated ground plane incorporating a rectangular slot cut out of the ground. Genetic algorithm is exploited to optimize the length of partial ground plane and the size and position of the rectangular slot. The overall size of the antenna is 28×29×1.6 mm3. Using the proposed fitness function, the ultra-wide band antenna configuration achieves an extensive impedance bandwidth spanning approximately 14.76 GHz (139.38%), covering frequencies from 3.21 GHz to 17.97 GHz for reflection loss S11 less than -10dB. The findings also indicate that the antenna exhibits a favorable peak gain of 3.7–6.24 dB in the desired band. Therefore, the proposed methodology proofs to be effective to acquire the best UWB behavior of the antenna.

Advancements in Indoor Precision Positioning: A Comprehensive Survey of UWB and Wi-Fi RTT Positioning Technologies

High-precision indoor positioning is essential for various applications, such as the Internet of Things, robotics, and smart manufacturing, requiring accuracy better than 1 m. Conventional indoor positioning methods, like Wi-Fi or Bluetooth fingerprinting, typically provide low accuracy within a range of several meters, while techniques such as laser or visual odometry often require fusion with absolute positioning methods. Ultra-wideband (UWB) and Wi-Fi Round-Trip Time (RTT) are emerging radio positioning technologies supported by industry leaders like Apple and Google, respectively, both capable of achieving high-precision indoor positioning. This paper offers a comprehensive survey of UWB and Wi-Fi positioning, beginning with an overview of UWB and Wi-Fi RTT ranging, followed by an explanation of the fundamental principles of UWB and Wi-Fi RTT-based geometric positioning. Additionally, it compares the strengths and limitations of UWB and Wi-Fi RTT technologies and reviews advanced studies that address practical challenges in UWB and Wi-Fi RTT positioning, such as accuracy, reliability, continuity, and base station coordinate calibration issues. These challenges are primarily addressed through a multi-sensor fusion approach that integrates relative and absolute positioning. Finally, this paper highlights future directions for the development of UWB- and Wi-Fi RTT-based indoor positioning technologies.

A Review of Multi-Sensor Fusion Techniques for Indoor Mobile Robot Navigation

The application of multi-sensor fusion technology in indoor mobile robot navigation and localization has been increasingly gaining attention, especially in complex indoor environments where achieving high-precision autonomous navigation poses a significant challenge. This review summarizes various sensor fusion methods, including the combination of Light Detection and Ranging (LiDAR), Inertial Measurement Unit (IMU), Ultra-Wideband (UWB), and others, with a focus on discussing the progress of fusion algorithms such as Extended Kalman Filter (EKF) and Adaptive Monte Carlo Localization (AMCL) in improving navigation accuracy and stability. In addition, this paper explores the application of visual Simultaneous Localization and Mapping (SLAM) methods incorporating deep learning in indoor robot navigation. Finally, the main challenges currently faced by multi-sensor fusion technology in robot autonomous navigation are analyzed, and future research directions are proposed, aiming to provide valuable references for researchers in the field.

Advanced design and analysis of dual element MIMO antenna for Ultra-Wideband Applications

This investigation uses the Genetic Optimization Method to convert a wide-band MIMO antenna into a UWB (3.1GHz–10.6 GHz) MIMO antenna. Initially, a 22 × 42, mm2 wideband 2X2 MIMO antenna was designed using commercial Flame Retardant-4 material. The structure of the antenna patch was designed using half-circular forms on the half-ground plane. The designed MIMO antenna operates throughout a large frequency range of 4.8–9.8 GHz. While it was successful in achieving broad band characteristics, this MIMO antenna was unable to reach ultra-wide band characteristics. The MIMO antenna was operated in UWB ranges by a parametric study, which indicated that the resonating characteristics can be significantly modified by inserting a rectangular slot into the ground plane. Throughout the operational range, it was important to be concerned about improved gain and good isolation. Accordingly, optimization was carried out in order to accomplish the essential, multi-objective goals. The difficult multi-objective design goal is now reduced to an optimization challenge by means of genetic algorithm based random search. One of the performance goals that this optimization strategy aimed to fulfil was an increase in isolation to –20 dB across the entire Ultra-Wideband, with S11 being below –10 dB from 3.1 to 10.6 GHz. It is recommended to randomly select the parameters from their respective ranges for this work. This led to the selection of an optimizer based on random searches. In the operating range, the UWB has a respectable gain of 4 dB to 6 dB and increased isolation to –20 dB, according to the genetic algorithm optimizer’s execution of the predefined multiple-objective task.

Compact UWB Slot Antenna With Dual‐Circular Polarization and Improvement of CP Performance

ABSTRACTThis study presents an ultrawideband (UWB) slot antenna with a dual‐circular (left‐ and right‐hand) circular polarization. The presented circularly polarized (CP) antenna involves 45° oriented patches cooperating with I‐ and L‐shaped stubs fed by a directional coupler. Using a directional coupler produces orthogonal electric fields to generate CP operation, and as a result of the cooperation between patches and stubs, antenna CP performance is improved. The fabricated antenna, including two microstrip ports, occupies an area of 50 × 50 × 1.016 mm3. By stimulating each antenna port independently, it is possible to obtain right‐hand circular polarization (RHCP) and left‐hand circular polarization (LHCP). The experiments show that the antenna being presented has an operating frequency of 116.14% (2.87–10.82 GHz) and an axial ratio bandwidth of 33.97% (7.11–10.02 GHz). Furthermore, a stable radiation pattern was also measured for the antenna, which had a maximum gain of 2.77 dBic in the operating frequency band.

Deep Kronecker LeNet for human motion classification with feature extraction

Human motion classification is gaining more interest among researchers, and it is significant in various applications. Human motion classification and assessment play a significant role in health science and security. Technology-based human motion evaluation deploys motion sensors and infrared cameras for capturing essential portions of human motion and key facial elements. Nevertheless, the prime concern is providing effectual monitoring sensors amidst several stages with less privacy. To overcome this issue, we have developed a human motion categorization system called Deep Kronecker LeNet (DKLeNet), which uses a hybrid network.The system design of impulse radio Ultra-Wide Band (IR-UWB) through-wall radar (TWR) is devised, and the UWB radar acquires the signal. The acquired signal is passed through the gridding phase, and then the feature extraction unit is executed. A new module DKLeNet, which is tuned by Spotted Grey Wolf Optimizer (SGWO), wherein the layers of these networks are modified by applying the Fuzzy concept. In this model, the enhanced technique DKLeNet is unified by Deep Kronecker Network (DKN) and LeNet as well as the optimization modules SGWO is devised by Spotted Hyena Optimizer (SHO) and Grey Wolf Optimizer (GWO). The classified output of human motion is based on human walking, standing still, and empty. The analytic measures of DKLeNet_SGWO are Accuracy, True positive rate (TPR), True Negative rate (TNR), and Mean squared error (MSE) observed as 95.8%, 95.0%, 95.2%, and 38.5%, as well as the computational time observed less value in both training and testing data when compared to other modules with 4.099 min and 3.012 s.

Low SAR ultra compact UWB vivaldi non-uniform slot antennas for breast cancer detection

Abstract Breast cancer is one of the growing issues among women. Current ultrawideband (UWB) antennas utilized for Microwave Imaging (MI) present several limitations, such as resolution and penetration trade-offs, large dimensions of the antennas degrade patient comfort, and clutter in the received signal. To tackle these restrictions, this study presents the design, fabrication, and testing of ultra-compact Vivaldi antennas based on the new Vivaldi non-uniform slot profile antenna (VNSPA) theory. These antennas, with their significant slot length reductions of 50 % and 60 %, and circuit area reductions of 72.74 % (Antenna A) and 81.8 % (Antenna B), hold great promise for modern wireless communication and medical fields. Antenna A and B provide matching S11 values of less than −11.36 dB and −10.21 dB and peak gains of 5.9 dBi and 6 dBi through 2.63–12.33 GHz and 3.16–14.34 GHz, respectively. Although Antenna B is 30.58 % smaller than Antenna A, it provides 13.24 % bandwidth (BW) with a 1.7 % gain enhancement, highlighting the significance of the exponential nonuniform slot profile (ENSP) shape on the antenna’s performance. Antenna B provides good Breast Cancer Detection (BCD) results through UWB MI. The simulation in this work, which is performed using computer simulation technology (CST) software, agrees well with the practical results to prove the antenna’s capabilities in detecting tumors in a breast. These results, like the directive stable radiation patterns and low specific absorption rate (SAR) values, ensure the proposed antennas are good candidates for modern wireless communication applications such as reader antennas in body area networks and high-resolution medical applications such as BCD.

UWB bandpass filter with tilted square shape ring topology sandwiched in the middle of interdigital structure

ABSTRACT This paper consists of compact novel design and high-performance ultra-wide band (UWB) bandpass filter (BPF) employed with square ring resonator (SRR) sandwiched between an interdigital structure (IDS). The unique combination of these microstrip resonators achieves a good selectivity across the passband with good rejection performance. The proposed structure also achieves less complexity and ease of fabrication. The passband extends from 4.2 GHz to 10.9 GHz with a notch band of 3 dB fractional bandwidth 88% centred at 7.6 GHz. The first passband in UWB BPF has minimum insertion loss as 0.59 dB and maximum return loss as 40.1 dB, whereas second passband has minimum insertion loss as 1.33 dB and maximum return loss as 36.62 dB. The presented filter structure is designed using Keysight Advance Design System (ADS). The simulated s-parameter characteristics performance is found to be in good agreement with the measured result.

Triple notched coplanar waveguide-fed novel ultrawide band antenna with time domain analysis

This research proposition introduces a novel microstrip antenna design that features triple notches for ultra-wideband (UWB) applications. The antenna, measuring 35.4 mm × 28.82 mm × 1.57 mm, incorporates rectangular and semi-circular slots, as well as a pentagonal stub. A modified U-shaped slot on the pentagonal stub creates one notched frequency band at 3.3–3.7 GHz. Additionally, two Split Ring Resonators (SRRs) are integrated into the antenna’s rear surface, resulting in two more notched bands at 5.1–5.8 GHz and 7.1–7.8 GHz. Operating within a frequency range from 3 to 11.2 GHz with VSWR ≤ 2, the antenna effectively excludes the triple stop bands at 3.3–3.7 GHz (11.4%), 5.1–5.8 GHz (12.8%) and 7.1–7.8 GHz (9.4%). The proposed antenna has been successfully prototyped and verified. An extensive result analysis has been conducted, confirming that the developed antenna is suitable for application in a range of wireless systems. Moreover, the article includes the implementation of an equivalent circuit for the proposed antenna.

Ultra Wideband High-Efficiency High-Power Amplifier Design by Simplified Output Matching Technique

Ultra Wideband High-Efficiency High-Power Amplifier Design by Simplified Output Matching Technique