A novel direction of arrival (DoA) estimation method based on amplifier-integrated active metasurface is proposed to find multisource directions by a single-channel system. Nonuniformly periodic time modulation (NPTM) the reduces hardware complexity taking full advantage spectral resources. As result, only partial elements are required achieve 2-D DoA estimation, while remaining can be redesigned and encoded control electromagnetic waves. Thus, adaptive beamsteering expected realize in...

To solve the problem of time-consuming, laborious, and low accuracy in magnetic map construction, a trajectory guided 2-D construction method is proposed this article. The absolute displacement calculated by inertial navigation system mapped to real construct map. precision constructed can reach 0.1141 m, mapping efficiency greater than 1800 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{\mathbf...

Pedestrian dead reckoning (PDR) using inertial and magnetic measurement unit (IMMU) is a current research hotspot that can be used to provide location-based services. The main challenges of the self-contained sensor-based PDR method are mainly sensor errors orientation estimation errors. In this paper, novel algorithm gait phase detection with strong adaptability proposed. variance magnitude angular rate adopted detect gait. experimental results show accurately distinguish swing stance foot...

In this letter, a dual-band isolation enhancement technique for two closely located planar inverted-F antennas (PIFAs) is proposed using compact spiral line (PSL) structure. The decoupling structure has the dimensions of less than 0.15λ × 0.1λ and can be flexibly applied to various practical multiple-input multiple-output systems. By employing structure, PIFAs (with port distance 0.1λ) achieve high better 20.3 26.7 dB within lower band (2.4-2.483 GHz) higher (5.25-5.9 GHz), respectively....

The pedestrian dead reckoning (PDR) positioning has small noise and high stability in the short term, but it cannot use for long term because of its cumulative error. received signal strength (RSS) fingerprint wide coverage no accumulative error, amount data leads to time discontinuous trajectory database, where wireless is poor result a Based on above method's issues, this paper proposes fusion indoor algorithm based PDR RSS fingerprint. This presents new filtering method comparison two...

In order to realize the ultrawideband suppression of simultaneous switching noise (SSN), a hybrid-embedded novel electromagnetic band-gap (EBG) structure is proposed. The presented EBG based on traditional Z-bridge embedded L-bridge structure. By HFSS software simulation and real test, results show that proposed can obtain SSN. Compared with L-bridge, effect greatly improved. This paper analyzes reason new achieve SSN equivalent circuit model Moreover, will lead signal integrity problems,...

In the context of protecting ecological environment and carbon neutrality, high-value recycling flexible polyurethane foam (F-PUF) scraps, generated in production process, is great significance to save petroleum raw materials reduce energy consumption. present study, F-PUF scraps were ground into powder by strong shear regrinding using two-roll mill then reused as a partial replacement polyol for re-foaming. A series characterizations employed investigate effect milling cycles, roller...

With the development of Internet-of-Things, urgent market demands have also provided a huge space for indoor pedestrian positioning systems (IPPS). Complementary filters (CF), Kalman and their various modifications are usually used to estimate orientation in foot-mounted IPPS. However, accuracy is still low because types electromagnetic interference diversity pedestrians' motion states. In this paper, an estimation algorithm proposed innovatively. First, nine-axes inertial/magnetic sensors...

Data are the cornerstone of digital sensors for Internet-of-Things (IoT) applications, which have been widely used in various fields from social development to human life. However, data failure because faults caused by or environmental causes may result sensor system failure. In order solve this issue, an online and credible integrity monitoring (DIM) method is proposed article. Overall, article contributes following ways. First, we model dividing it into format failure, timing value Second,...

With the development of Internet Things (IoT) technology, people's demand for indoor location-based services is growing. Indoor magnetic field has a wealth fingerprint information that can be combined with position stamps to construct an map (IMM). Localization scenarios based on IMM include personnel attendance, equipment tracking, and fire emergency, etc. However, localization technology complicated, accuracy generally low, result lacks credibility due fluctuation field. Therefore, it...

This letter demonstrates the dual transmission zeros (TZs) of bandpass elliptic prototype filters that can be directly implemented with two resonators in microstrip. An experimental filter based on proposed alternate circuits is designed and fabricated. In order to improve rejection stopband, additional TZs are introduced filter. By means implementing an microstrip, insertion loss presented less than 0.8 dB, Δf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Carbon nanotube (CNT), as reinforcing agents in natural rubber (NR), has gained a large amount of consideration due to their excellent properties. Uniform dispersion CNT is the key obtaining high-performance NR nanocomposites. In this contribution, novel ultrasonic grinding method with waterjet-produced powder (WPRP) carrier proposed. Microscopic morphologies show that Xanthium-like structure WPRP core and CNTs spikes formed, which significantly improves matrix simultaneously strengthens...

This article presents a dual-band substrate integrated waveguide (SIW) band-pass filter based on complementary split ring resonators (CSRRs) and multimode cavity resonator. The consists of square SIW cavity, CSRRs several perturbed metallic vias. resonant frequencies the TE102 mode form first passband, TE201 TE202 second passband. upper lower cutoff two passbands can be adjusted independently by changing dimensions as position vias size cavity. Finally, with center 9.8 13.5 GHz is designed...

Magnetic data obtained from a magnetic sensor usually fluctuate in certain range, which makes it difficult to estimate the heading accurately. In fact, information is submerged noise because of all kinds electromagnetic interference and diversity pedestrian's motion states. order solve this problem, new adaptive algorithm based on (typically) right-angled corridors building or residential buildings put forward process information. First, 3D indoor localization platform set up MPU9250. Then,...

With the development of Internet Things (IoT), people's demand for location-based services is increasingly urgent. Based on magnetometer, accelerometer, and rate gyro, i.e., MARG sensors, position attitude estimation methods such as complementary filter (CF), Kalman (KF), their various modifications have been research hot spot. However, CF-based are empirical lack robustness; KF-based memory-free observers, whose solution may diverge when lacks uniform observability. In this article, a...

To reinforce natural rubber latex foam, fumed silica and precipitated are introduced into foam prepared using the Dunlop process as fillers. Four types of silica, including Aerosil 200 (hydrophilic silica), Reolosil DM30, R972 (hydrophobic Sipernat 22S (precipitated investigated. The with added presents better mechanical physical properties compared non-silica foam. hydrophobic nature has dispersion in to hydrophilic silica. specific surface area particles (BET) also significantly influences...

The micro-electromechanical systems (MEMS) digital sensors have been widely used in various fields, e.g., industrial application, navigation and positioning, etc. In order to make full use of the resolution a sensor, people tend choose lower range, which often leads out-of-range problem. fact, it is tradeoff among resolution, efficiency. It possible optimize two these, but difficult all three. Therefore, tri-adaptive method, i.e., adaptive sampling frequency, output proposed this paper. We...

Generally, the positioning system is based on wearable inertial and magnetic measurement unit (IMMU), but its algorithm relies heavily wearing position, there no adaptive for position. To solve this problem, paper proposes a human body topology recognition (BTR) gait information, which can accurately real time identifies six typical positions. The average rate 99.11%, real-time performance controlled within 1.2 s. As priori detection BTR extended. Experimental results show that proposed...

Indoor positioning system based on MEMS (Micro-electromechanical Systems) technology is really self-measurement which does not depend any external signal and other infrastructure. Inertial/magnetic sensors are typically composed of three orthogonal gyroscopes, accelerometers magnetometers, can form AHRS (attitude heading reference system) pedestrian dead reckoning system. However, the inertial/magnetic offer good short term in indoor environments, but absolute position fixes medium- to long-...

Indoor magnetic map (IMM) based on field fluctuations can be used in assisted indoor positioning and navigation, etc. However, many IMM mapping solutions are time-consuming, labor-intensive, high-cost, which limit the development application of IMM. To solve issues accuracy, efficiency, cost collaboratively, we absorbed idea simultaneous localization (SLAM) method, proposed a human-interactive method low-cost magnetometer, accelerometer, rate gyro, i.e., MARG sensors. First, defined as...

Low-temperature mechanical chemical devulcanization is a process that can produce reclaimed rubber with exceptional properties. However, the inadequacy and low efficiency of have significantly restricted its application. To address issues, alcoholic amines, including hydroxyethyl ethylenediamine (AEEA), ethanolamine (ETA), diethanol amine (DEA), are utilized as devulcanizing agents to promote process. Careful characterizations conducted reveal mechanism depict performances rubbers. Results...