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INTRODUCTION: Individuals with visual impairments face a variety of challenges in their daily lives, from daily activities to physical world navigation. One of the biggest challenges is the ability to travel around safely and independently. This challenge is complicated and stressed to the visually impaired as the inability to perform obstacles or ground plane checking will result in severe injury or even death.OBJECTIVES: This work aims to prove the outdoor performance of the developed solution in detecting and recognising the frontal ground plane conditions.METHODS: The proposed model uses a LiDAR module as a distance-measuring tool to perform ground plane checking.RESULTS: In the selected outdoor path-based scenarios, the ground plane checking system succeeded in achieving an overall recognition rate of 93.10%, with an overall false positive rate of 2.72% and average false negative rate of 4.25%.CONCLUSION: Overall, the findings showed the ability of the proposed model to provide effective frontal ground plane checking for the visually impaired.

3D lidar-based simultaneous localization and mapping (SLAM) is a well-recognized solution for mapping and localization applications. However, the typical 3D lidar sensor (e.g., Velodyne HDL-32E) only provides a very limited field of view vertically. As a result, the vertical accuracy of pose estimation suffers. This paper aims to alleviate this problem by detecting the absolute ground plane to constrain vertical pose estimation. Different from the conventional relative plane constraint, this paper employs the absolute plane distance to refine the position in the z-axis and the norm vector of the ground plane to constrain the attitude drift. Finally, relative positioning from lidar odometry, constraint from ground plane detection, and loop closure are integrated under a proposed factor graph-based 3D lidar SLAM framework (AGPC-SLAM). The effectiveness is verified using several data sets collected in Hong Kong.

Ground segmentation is a crucial task in the field of 3D LiDAR perception for autonomous driving. It is commonly used as a preprocessing step for tasks such as object detection and road extraction. However, the existing ground segmentation algorithms often struggle to meet the requirements of robustness and real-time performance due to significant variations in ground slopes and flatness across different scenes, as well as the influence of objects such as grass, flowerbeds, and trees in the environment. To address these challenges, this paper proposes a staged real-time ground segmentation algorithm. The proposed algorithm not only achieves high real-time performance but also exhibits improved robustness. Based on a concentric zone model, the algorithm filters out reflected noise points and vertical non-ground points in the first stage, improving the validity of the fitted ground plane. In the second stage, the algorithm effectively addresses the issue of undersegmentation of ground points through three steps: ground plane fitting, ground plane validity judgment, and ground plane repair. The experimental results on the SemanticKITTI dataset demonstrate that the proposed algorithm outperforms the existing methods in terms of segmentation results.

A compact MIMO antenna with enhanced isolation and the ability to switch the frequency bands is an attractive candidate for the current multifunctional high-speed portable wireless devices. To achieve this objective, a simple and novel compact dual-mode 4-port MIMO configuration for WiMAX and WLAN standards has been introduced in this work. The compactness of the MIMO geometry (34 mm × 34 mm) is due to compact switchable curve-shaped monopoles arranged closely over a loop-shaped continuous ground plane. The ground plane is defected by etching open-ended slots to suppress the surface current flow between the elements. As antenna elements switch between mode-1 (WiMAX band) and mode-2 (WLAN band), the DGS slots are also switchable to enhance isolation across both bands. The switchable DGS slots function as bandstop filters and thus isolate the elements by 40 and 41 dB in the accomplished frequency bands. The intented MIMO antenna reports a − 10 dB return loss bandwidths of 400 MHz (3.3–3.7 GHz) and 1100 MHz (4.75–5.85 GHz) in mode-1 and mode-2, respectively. The diversity metrics of envelope correlation coefficient < 0.002, diversity gain ≈ 10 dB, total active reflection coefficient < − 10 dB, and channel capacity loss < 0.4 b/s/Hz, ensure excellent diversity/MIMO performance. The optimized 4-port MIMO configuration is fabricated, and measured results are compared with the simulated ones to validate the introduced technique. The MIMO antenna's compact form factor and excellent antenna/diversity characteristics confirm its potentiality for use in portable multifunctional wireless devices.

A unique coplanar-waveguide (CPW)-fed circularly polarised square slot antenna with enhanced impedance bandwidth (IBW) is presented. The antenna structure includes a pair of rectangular-shaped notches located at two opposite corners of the slot for achieving a significantly enhanced IBW of 12.06 GHz (2.76–14.82 GHz), and a pair of reverse L-shaped ground arms in the slot for realising circularly polarised radiation with 1.86 GHz (4.27–6.13 GHz) bandwidth. This proposed technique has the advantages of covering the whole of the ultra-wideband spectrum (3.1–10.6 GHz), an average gain of 3 dBi and a reduced antenna size of 25 × 25 × 0.8 mm3.

This article demonstrates a portable ultrawideband (UWB) diversity antenna with capability of rejecting WLAN band. A circular split ring resonator (SRR) slot is etched out in the patch for filtering out the interference due to WLAN band centered at 5.2 GHz. A partial common ground plane with T-shaped stub is employed for high isolation. A fair correlation is reported between the simulated and experimentally measured findings with |S 11 | < −10 dB in the operational band. The measured isolation of |S 21 | < −20 dB along with satisfactory diversity performance metrics prove the utility of suggested antenna for UWB MIMO applications.

In this paper, a monopole Ultra-wide band (UWB) textile antenna is designed and analyzed for RF Wireless Energy Harvesting (RFEH). The intended antenna exhibits its excellent characteristics with a compact dimension of 80 60 mm2. In the front plane of the proposed antenna, the microstrip line fed enneagon (nonagon) shaped patch structure has been modified by incorporating rectangular and semi-circular shaped slots. On the other hand, the bottom plane consists of a partial ground plane and a rhombus shaped parasitic radiating structure has been incorporated at the backside of the substrate to utilize the available space above the partial ground to obtain wide impedance bandwidths. Moreover, textile materials are used in this design to improve flexibility and conformability of the designed antenna. From the simulated results, the proposed antenna achieves a wide impedance bandwidth from 1.54 GHz to 12.79 GHz S11 10 dB. Moreover, the maximum gain is 5.03 dB, and the peak radiation efficiency is 95 %. With merit characteristics, the proposed design can be well applied to harvest RF energy. The results show that the proposed miniaturized UWB antenna system can cover the bandwidth requirements of entire UWB systems (3.1-10.6 GHz) and also supports several wireless communication standards such as Wi-Fi (2.4-2.484 GHz, 5.15-5.35 GHz, 5.725-5.825 GHz, 5.925-7.125 GHz), 4G LTE (2.3-2.39 GHz, 2.555-2.655 GHz), Sub 6 GHz 5G FR-1 NR bands (1-6 GHz), and X-band (8-12 GHz).

A novel design of circular microstrip antenna by employing rectangular slots cut modified ground plane profile is proposed, on thinner FR4 substrate. With the modifications in the resonant mode current paths and the fringing fields in the antenna cavity, as compared with a conventional ground plane design, proposed configuration yields 5.6% reduction in the resonance frequency, three times increase in the bandwidth, gain improvement by 0.5 dBi, and more than 40 dB reduction in the cross-polar level. As against the reported configurations in the literature, results obtained in the proposed design are better considering a single patch design, while employing a thinner and lossy substrate. The equivalent configurations of the proposed design can find applications in GSM 900 or Bluetooth and WLAN applications.

FinFETs are popular and forefront runner in integrated circuits (ICs) technology due to exceptional scalability and suppressed short channel effects (SCEs). The bottom spacer (BP) concept is adopted in FinFET to achieve ameliorated short-channel, reduced self heating issues and to solve width quantization effect. The dual-material-gate (DMG) concept provides novel features like threshold voltage roll-up, transconductance enhancement and suppression of SCEs by work function engineering. Further, the ground-plane (GP) concept is also introduced to minimize the interaction between source and drain region which results in suppressed drain induced barrier lowering (DIBL). This paper investigates the systematic analysis of novel DMBSGP FinFET. The electrical performance parameters are extracted for different bottom spacer height (BSH) and workfunction differences (∆W). The analog/RF figure of merits (FOMs) such as transconductance (g m ), output conductance (g d ), transconductance generation factor (g m /I D ), early voltage (V EA ), intrinsic gain (A V ), cut-off frequency (f T ), transconductance frequency product (TFP), gain frequency product (GFP) and gain transconductance frequency product (GTFP) are examined for different BSH of DMBSGP FinFET using 3-D ATLAS device simulator.

The deployment of wireless devices has increased exponentially in recent years, not only for mobile applications but also for IoT. Typically, these IoT devices exchange data with other devices by means of wireless connections, where battery consumption depends on the antenna system’s efficiency. In applications where long battery life and reliable transmission are essential, improving the efficiency of the antenna is crucial. This study aims to investigate how shaping the ground plane of a wireless device can enhance bandwidth and antenna efficiency, specifically in low-frequency bands of 824–960 MHz, a common frequency band used in IoT where transmitting a small amount of data provides long battery life. Specifically, this work shows that by adding a slot in the ground plane, the current distribution is enlarged, which enables the excitation of its fundamental mode and, consequently, enhances the bandwidth and antenna efficiency by 2 dB. This approach is assessed using three different printed circuit boards (PCBs) that aim to characterise different form factors of IoT devices. A physical prototype is built to validate the results obtained in simulations.