In this paper, we investigate the network connectivity of wireless sensor networks with directional antennas. In particular, we establish a general framework to analyze the network connectivity while considering various antenna models and the channel randomness. Since existing directional antenna models have their pros and cons in the accuracy of reflecting realistic antennas and the computational complexity, we propose a new analytical directional antenna model called the iris model to balance the accuracy against the complexity. We conduct extensive simulations to evaluate the analytical framework. Our results show that our proposed analytical model on the network connectivity is accurate, and our iris antenna model can provide a better approximation to realistic directional antennas than other existing antenna models.
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http://dx.doi.org/10.3390/s17010134 | DOI Listing |
Micromachines (Basel)
December 2024
College of Electronic and Electrical Engineering, Henan Normal University, Xinxiang 453600, China.
A novel common-aperture miniaturized antenna with wideband and dual-polarized characteristics is proposed, which consists of a circularly polarized (CP) and a linearly polarized (LP) antenna. The circularly polarized antenna stacked on the upper layer adopts asymmetrical ground and introduces the patch and T-type feed network. On this basis, the meshed reflector structure, which also works as a ground plane for the LP antenna, is added to reduce the influence on circular polarization and achieve directional radiation.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
The National Key Laboratory of Radar Detection and Sensing, Xidian University, Xi'an 710071, China.
In order to achieve high accuracy in interferometric direction-finding systems, antennas with a stable phase center in the working bandwidth are required. This article proposes a miniaturized loaded open-boundary quad-ridge horn (LOQRH) antenna with dimensions of 40 mm × 40 mm × 49 mm. First, to stabilize the phase center of the antenna, the design builds on the foundation of a quad-ridge horn antenna, where measures such as optimizing the ridge structure and introducing resistive loading were implemented to achieve size reduction.
View Article and Find Full Text PDFNat Commun
January 2025
Institute of Electromagnetic Space, Southeast University, Nanjing, China.
Holographic multiple-input multiple-output (MIMO) method leverages spatial diversity to enhance the performance of wireless communications and is expected to be a key technology enabling for high-speed data services in the forthcoming sixth generation (6G) networks. However, the antenna array commonly used in the traditional massive MIMO cannot meet the requirements of low cost, low complexity and high spatial resolution simultaneously, especially in higher frequency bands. Hence it is important to achieve a feasible hardware platform to support theoretical study of the holographic MIMO communications.
View Article and Find Full Text PDFInsect Sci
January 2025
Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China.
Oviposition behavior in insects has received considerable attention, but studies have mainly focused on the antennae, neglecting the role of the ovipositor. In this study, we investigated the functional characteristics of the ovipositor in oviposition site selection by the fall armyworm (FAW) Spodoptera frugiperda, a destructive invasive pest of maize and other cereals. In oviposition choice assays females exhibited significant repellency to isothiocyanate (ITC), volatiles specific to non-preferred cruciferous plants.
View Article and Find Full Text PDFISA Trans
January 2025
School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, BT9 5BN Belfast, United Kingdom. Electronic address:
In recent years, exoskeleton robots have attracted great interest from researchers in the area of robotics due to their ability to assist human functionality improvement. A wearable lower limb exoskeleton is aimed at supporting the limb functionality rehabilitation process and to assist physical therapists. Development of a stable and robust control system for multi-joint rehabilitation robots is a challenging task due to their non-linear dynamic systems.
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