Wideband Sensor Research Articles

Overview of the use of oxygen sensors in automotive applications

In the process of combustion, the air-fuel ratio is important for control strategies to reduce fuel economy and improve engine performance. Oxygen sensors are key elements in electronic fuel injection systems to indicate the oxygen content and send electrical signals to the electronic control unit. Starting with the first generation of oxygen sensors, which had limited applications, all automotive manufacturers now use wideband sensors to detect oxygen concentration with rapid reaction and linear output characteristics. Also, these new sensors provide accurate information for a wide range of air coefficients (λ = 0.65-2.4), improving combustion efficiency. In this paper, several types of narrowband and wideband sensors were analyzed, measuring the activation temperature for each sensor until a reliable signal was obtained.

A new model of ultra wideband sensors based interactive system

Camera Based Interactive Systems have found their application in various fields of human activity, such as education, industry, entertainment, healthcare, public order, etc. It could be noted that in the characteristics of such a system, certain shortcomings or weaknesses could be highlighted. To reduce these weaknesses, a new model, based on digital communication devices in the wideband radio frequency spectrum is proposed. The technology used is ultra-wideband based, through the construction of a wireless sensor network. This paper proposes a model of an ultra-wideband wireless sensor-based interactive system that implements the spatial orientation approach and the precise local positioning approach. A synthesis of the new model comprises four phases.

Novel Meta-Fractal Wearable Sensors and Antennas for Medical, Communication, 5G, and IoT Applications

Future communication, 5G, medical, and IoT systems need compact, green, efficient wideband sensors, and antennas. Novel linear and dual-polarized antennas for 5G, 6G, medical devices, Internet of Things (IoT) systems, and healthcare monitoring sensors are presented in this paper. One of the major goals in the evaluation of medical, 5G, and smart wireless communication devices is the development of efficient, compact, low-cost antennas and sensors. Moreover, passive and active sensors may be self-powered by connecting an energy-harvesting unit to the antenna to collect electromagnetic radiation and charge the wearable sensor battery. Wearable sensors and antennas can be employed in smart grid applications that provide communication between neighbors, localized management, bidirectional power transfer, and effective demand response. A low-cost wearable antenna may be developed by etching the printed feed and matching the network on the same substrate in the printed antenna. Active modules may be placed on the same dielectric board. The antenna design parameters and a comparison between the computation and measured electrical performance of the antennas are presented in this paper. The electrical characteristics of the new compact antennas in the vicinity of the patient’s body were simulated by using electromagnetic simulation techniques. Fractal and metamaterial efficient antennas and sensors were evaluated to maximize the electrical characteristics of smart communication and medical devices. The dual- and circularly polarized antennas developed in this paper are crucial to the evaluation of wideband and multiband compact 5G, 6G, and IoT advanced systems. The new efficient sensors and antennas maximize the system’s dynamic range and electrical characteristics. The new efficient wearable antennas and sensors are compact, wideband, and low-cost. The operating resonant frequency of the metamaterial antennas with circular split-ring resonators (CSRRs) may be 5% to 9% lower than the resonant frequency of the sensor without CSRRs. The directivity and gain of the metamaterial fractal antennas with CSRRs may be up to 3 dB higher than the antennas without CSRRs. The directivity and gain of the metamaterial fractal passive sensors with CSRRs may be up to 8.5 dBi. This study presents new wideband active meta-fractal antennas and sensors. The bandwidth of the new sensors is around 9% to 20%. At 2.83 GHz, the receiving active sensor gain is 13.5 dB and drops to 8 dB at 3.2 GHz. The receiving module noise figure with TAV541 LNA is around 1dB.

Low-Cost L-Band to Ku-Band Frequency Reconfigurable BAR64-02V Controlled Antenna for Satellite, Military, and Radar Applications

A miniaturized edge-fed multi-band wideband (WB) sensor complementary split ring resonator (CSRR) and two folded pedal arms loaded antenna for wireless, ISM, military, Radar, and satellite applications is fabricated, tested, and investigated. The reduced ground plane at the bottom to makes the gain positive and leads to improvement in the radiation efficiency. Loading of antenna patch with two folded bicycle pedal-shaped arms results in an increased total electrical length and hence antenna could be tuned up to higher frequency bands. The appended two folded pedal arms enhance the value of gain and CSRR loading introduces additional resonant frequencies below −10dB reflection coefficient. The symmetrical ground width compression results in total antenna size miniaturization to 43.33% concerning the conventional circular microstrip antenna designed at a frequency of 2.45GHz. The antenna has a bidirectional radiation pattern with a gain of 5.21dBi and a radiation efficiency of 90.50%. The antenna exhibits four bands (2.13–2.58GHz), (2.77–3.89GHz), (5.65–6.56GHz), and (7.77–12.98GHz) within a frequency sweep of 1–15GHz, therefore it, is the most suitable element for Bluetooth, PCS, ISM band, 3G/4G/5G, Wi-MAX/WLAN/ Wi-Fi, and wireless, satellite, military, and RADAR applications. These bands are frequency reconfigured by two BAP64-02V PIN diodes in the pedal-arms fold locations with four switching combinations. The measured (frequency sweep: 1–23GHz) and simulated antenna reflection coefficient values are found in match except for a frequency range of 12–14 GHz. The antenna was fabricated on a low-cost FR-4 that holds well <12 GHz frequencies, and >12 GHz frequencies values this shows nonlinear and frequency dispersion.

An Integrated UWB-IMU-Vision Framework for Autonomous Approaching and Landing of UAVs

Unmanned Aerial Vehicles (UAVs) autonomous approaching and landing on mobile platforms always play an important role in various application scenarios. Such a complicated autonomous task requires an integrated multi-sensor system to guarantee environmental adaptability in contrast to using each sensor individually. Multi-sensor fusion perception demonstrates great feasibility to compensate for adverse visual events, undesired vibrations of inertia sensors, and satellite positioning loss. In this paper, a UAV autonomous landing scheme based on multi-sensor fusion is proposed. In particular, Ultra Wide-Band (UWB) sensor, Inertial Measurement Unit (IMU), and vision feedback are integrated to guide the UAV to approach and land on a moving object. In the approaching stage, a UWB-IMU-based sensor fusion algorithm is proposed to provide relative position estimation of vehicles with real time and high consistency. Such a sensor integration addresses the open challenge of inaccurate satellite positioning when the UAV is near the ground. It can also be extended to satellite-denied environmental applications. When the landing platform is detected by the onboard camera, the UAV performs autonomous landing. In the landing stage, the vision sensor is involved. With the visual feedback, a deep-learning-based detector and local pose estimator are enabled when the UAV approaches the landing platform. To validate the feasibility of the proposed autonomous landing scheme, both simulation and real-world experiments in extensive scenes are performed. As a result, the proposed landing scheme can land successfully with adequate accuracy in most common scenarios.

Characterization Challenges of a Low Noise Charge Detection ROIC

This article presents the experimentally characterized performance of a low noise and wideband sensor readout integrated circuit (ROIC). The ROIC is designed to detect small amounts of charge generated by a silicon p-i-n detector as a result of particle detection, with very high time resolution and limited power consumption. The architecture of the ROIC permits the analog components of the particle readout to be designed with a reduced bandwidth by implementing the so-called intersymbol interference (ISI) cancellation technique, which improves the noise performance, while reducing the deterministic ISI-induced errors associated with the narrowband circuit; hence, a low error rate (ER) can be maintained. The readout is designed to detect 160 aC charge portions delivered randomly by the detector at a maximum of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 10^{8}$ </tex-math></inline-formula> events/s with a small average ER while consuming 2.85 mW. Detailed information about the ROIC designed in 65-nm CMOS technology, and the simulated performance, are already reported in a previous publication. This article aims to present the challenges related to the design of the test setup and the obtained experimental results with the first prototype of the ROIC, as well as to discuss the data acquisition process.

Wideband Reflector and Analogue Electromagnetically Induced Reflection in Metamaterials

Metamaterials are highly demanded for advanced applications in absorbers, sensors, and filters. However, metamaterial reflectors, especially broadband reflectors, remain challenging. In this paper, we theoretically investigate a wideband metamaterial reflector which consists of cross shaped graphene strips and a silica (SiO2) substrate. The cross shaped graphene strips are coated on the top of the structure, and the cross shape rotated 45° graphene strips are spun on the bottom of it. The calculated reflection can be tuned through length and width of the graphene strips. By comparison, not only broadband reflection but also analogue electromagnetically induced reflection (EIR) can be realized. Moreover, the structure can generate a bi-directional broadband reflection of insensitive polarization. This kind of bi-directional reflector at microwave frequencies is obtained because the top and bottom graphene strip structures are similar. We employ the electric field distribution of the designed structure to elucidate the mechanism of the analogue EIR effect. We further discuss the influence of incident angle on the analogue EIR effect. Such a bi-directional reflector can be potentially applied to a wideband reflector, antenna, and sensor.

Power System Transient Current Sensor Based on Magnetoresistance Effect

Aiming at the problem that the mixed use of overhead lines and cables causes serious refraction and attenuation of the traveling wave signal in propagation, which makes the traditional traveling wave sensor unable to adapt to the weak signal identification and recording requirements. A wideband sensor for detecting transient current signal of power system is developed. The detection principle of the anisotropic magnetoresistive sensor is analyzed, and the tiny signal precision differential amplifier circuit is designed. Based on the actual situation of the power system, a corresponding test environment was built to conduct transient current transfer tests. The experimental results show that the sensor has a high linearity in the 0-5MHz bandwidth, and is suitable for the extraction of various transient signals, especially in the power system traveling wave protection has high application value.

High-Frequency Current Transformer Design and Implementation Considerations for Wideband Partial Discharge Applications

High-frequency current transformers are popular noninvasive inductive wideband sensors. Despite the simplicity in design and operational principle, implementation of such sensors for partial discharge (PD) applications requires careful consideration, particularly in the higher frequency range where traveling wave attenuation and distortion are relevant. First, the role of design variables, including core materials, winding design, and shielding practices on sensor sensitivity and frequency characteristics (transfer impedance), is presented. Next, the suitability of the constructed sensors for PD applications is assessed. The designed wideband sensors are suitable for laboratory applications with standard measurement circuits and controlled conditions. The low-level magnitude and frequency spectrum of the discharge pulses hinders signal integrity in relation to the placement of the sensors within the measurement circuit, signal amplification, and pulse repetition rate (pulse resolution). To enable the most stringent detection levels under 1 pC, efforts are needed in distortionless amplifier design and interference mitigation.

Wideband MEMS vibration sensor for machine activity monitoring

Wideband MEMS vibration sensor for machine activity monitoring

Experimental comparison of acoustic emission sensors in the detection of outer race defect of angular contact ball bearings by artificial neural network

In this paper, three different types of acoustic emission sensors have been applied to detect the outer race defect of angular contact ball bearings. The sensors include R6a, which is a general-purpose, WSa, wideband sensor and Pico, miniature sensor. All three sensors differ in size and operational frequency range and sensitivity. In this research, using signal analysis methods, different features and parameters in time-domain have been extracted from the signal and different four states (healthy and three faulty states) have been identified based on them. An artificial neural network used for separating, detection and classification of defect sizes. In the first comparison of the signals, the results showed that R6a was better for absorbing acoustic emission energies and for data acquisition and processing than the other two sensors. But by creating the neural network and selecting different parameters, therefore all three sensors could be useful in diagnosing the faults.

Singular Spectrum Analysis-Based Algorithm for Vitality Monitoring Using M-Sequence UWB Sensor

Recently, noninvasive vital signs detection is widely used in through the wall (TTW) human detection and healthcare monitoring. In indoors and TTW environments, low signal to noise ratio make the detection of the weak vital signs difficult, and causes errors in the estimation of heartbeat, respiration rate. In this paper, different techniques are applied to the signal collected using a M-sequence ultra wideband sensor from the human subject, in order to suppress the clutter, detect the target range and estimate the heartbeat and respiration rate. First, moving average method is used to remove the stationary clutter. Next, Singular Value Decomposition (SVD) is applied to cancel the non-stationary clutter. Then, variance analysis is applied to estimate the range; when range has been detected, one dimensional Singular Spectrum Analysis (SSA) is applied to the range bin containing the subject data. It is observed that SSA completely succeeds to decompose the signal into heartbeat and respiration signal and a collection of unwanted signals as clutter, noise, and harmonics. Finally, Fast Fourier transform (FFT) is used for the estimation of the heartbeat and respiration rate. Comparison results show that the proposed algorithm outperforms a reference SVD based algorithms for heartbeat and respiration rate estimation.

Study on the Technology of Ultra-high Sensitive Wide-band Magnetic-feedback Inductive Magnetic Sensor

It analyses the composition and principle of high-sensitive wide-band magnetic-feedback inductive magnetic sensor to fulfil the demand of high-sensitive wide-band magnetic sensor in geological exploration. It studies main factors to the performance of wide-band magnetic sensor, such as turns of coils, core material features, and amplifier noise, specifies section-wise coil winding, the type and dimension of core material, and designs low-noise high-impedance LF chopping amplifier channel and composite amplifier with HF amplifier channel. The noise of magnetic sensor at 1 Hz is better than 10-4nT/Hz1/2, at 100Hz-1kHz band the noise floor is close to SQUID which can reach 10-6nT/Hz1/2. The magnetic sensor works at wide frequency band (0.0001Hz-10kHz) and ultra-low noise, which can meet the requirements of both AMT and CSAMT.

A comprehensive study of mechanical and acoustic properties of selective laser melting material

In this research work, four groups of selective laser melted specimens were built from AlSi10Mg-0403 powder. Each group represents the direction with respect to the bed in which the specimens are built (X, Y, Z and 45° orientation). The mechanical properties of the specimens are characterized in terms of yield strength, ultimate tensile strength, Young’s modulus and elongation at break. In addition to that, the acoustic emission (AE) during the testing was monitored using wide-band high-accuracy piezoelectric sensors. The AE results were related to the mechanical characteristics of the specimens in terms of the acoustic parameter-based data, the peak amplitude, cumulative energy and count rate. The mechanical results show that the specimens built along the z direction have relatively lower strength and it can be attributed to the borderline porosity formed during the SLM process. The acoustic results can identify the critical points of failure under loading. The AE technique proves to be a powerful tool in characterizing the mechanical property and can unveil the concealed information which cannot be identified directly from the mechanical results.

Developing smart multi-sensor monitoring for tool wear in stamping process

Tool wear and galling are of significant concern in the automotive stamping industry, due to the increase in use of higher strength sheet steels in automotive structures and reduced lubrication during stamping production. There are many methods explored in the literature and applied in industry to combat wear in stamping, including new die materials and coatings, alternative lubrication systems and better predictive models. However, smart condition monitoring will continue to be relevant in conjunction with these methods because it can provide further opportunities for production quality and cost improvements, despite the advancements of these other methods. This paper explores the use of multiple sensors and multiple signal processing techniques, aimed at developing a smart multi-sensor method to monitor galling wear. The three main sensors and corresponding signal processing techniques examined are: (i) measurement of punch force signatures analyzed via Principal Component Analysis (PCA); (ii) acoustic emissions signals measured via wideband sensors and examined using time and frequency domain features; (iii) measurement of audio signals in the audible frequency range analyzed via blind signal separation techniques. For all techniques, a semi-industrial stamping test was used to provide realistic production-type conditions, albeit with accelerated wear rates. The relationship between the key outputs from the three sensor/analysis methods were directly compared to a new quantitative measure of galling wear severity. Based on these results, it was observed that a multi-sensor approach for wear condition monitoring provides an opportunity for the development of a smart monitoring tool that can actively track the progression of wear.

An embedded wide-band sensor for PD on-line monitoring of XLPE cable joint

Monitoring partial discharge (PD) activities in the joint of cross-linked polyethylene (XLPE) cables has attracted much attention due to its extensive application and high fault rate. In this paper, we designed a wide-band sensor with simple configuration, which was embedded in the outer semi-conductive layer of the cable. Based on the analysis of circuit and antenna models, the structural parameters of sensor were determined, and it was found that the effective bandwidth reached up to 500 MHz. In addition, the sensor had a quick response to the pulse with a rising time longer than 2 ns by testing its square response, as well as a linear input-output characteristic and a sensitivity of 3 pC. At last, the sensor was applied to insulation defect type identification in the cable joint. As for three common defects, both the single PD pulse and PD patterns showed distinct. These indicated that the sensor had a potential application prospect in the PD online detection for cable joint.

Sensitive readout of implantable microsensors using a wireless system locked to an exceptional point

Exceptional points are degeneracies in physical systems at which both the underlying eigenvalues and eigenvectors of the system coalesce. They originated in theoretical explorations of quantum mechanics, but are of increasing value in photonics, acoustics and electronics because their emergence in physical systems with controlled gain and loss can dramatically alter the response of a system. In particular, systems biased at exceptional points can exhibit an amplified response to a small perturbation, enabling greatly enhanced sensitivity for certain resonant sensors. In biomedicine, implanted electronic sensors based on resonant inductor–capacitor (LC) circuits can be used to monitor internal physiological states, but their capabilities are currently limited by the low sensitivity of existing wireless interrogation techniques. Here we show that a reconfigurable wireless system locked to an exceptional point can be used to interrogate in vivo microsensors with a sensitivity 3.2 times the limit encountered by existing schemes. We use a controller that maximizes the abruptness of a parity–time-symmetry phase transition to operate a reconfigurable circuit at an exceptional point and maintain enhanced sensitivity. With this approach, we demonstrate robust readout of LC microsensors (with diameters of 900 μm) that are subcutaneously implanted in a rat, and show that it can be used for wideband sensor interrogation for measurement of the resonant frequencies of single and multiple sensors. A reconfigurable wireless system locked to an exceptional point can be used to interrogate in vivo inductor–capacitor microsensors with a sensitivity 3.2 times beyond the limit of conventional readout schemes.

Comparative analysis of robust extended Kalman filter and incremental smoothing for UWB/PDR fusion positioning in NLOS environments

Ultra wide band (UWB) sensors are widely used for indoor positioning; however, in many practical scenarios UWB signals are obscured by people, goods or other obstacles. This results in signal intensity attenuation, multipath effect and even signal loss, which causes a sharp decline in positioning accuracy. Fusion of pedestrian dead-reckoning (PDR) and UWB is an effective method to achieve high-accuracy positioning under non-line of sight conditions. While traditionally Bayesian filters, such as extended Kalman filter (EKF) and particle filter have been used for UWB/PDR fusion, recently Incremental Smoothing has been shown to achieve high accuracy in other application domains. In this paper, incremental Smoothing based on Tukey kernel function is proposed to fuse UWB and PDR data. We compare the performance of Incremental Smoothing with state of the art fusion algorithms based on EKF, and show that the incremental smoothing algorithm can achieve real-time positioning while exhibiting stronger robustness against intermittent noise, continuous noise and continuous interruption abnormality of UWB data.

In-Cylinder CO2 Sampling Using Skip-Firing Method

Skip-firing (or cylinder de-activation) was assessed as a method of sampling CO2 directly in the cylinder at higher speeds than previously possible. CO2 was directly sampled from one cylinder of a 1 L three-cylinder gasoline engine to determine the residual gas fraction (RGF) using a fast response CO/CO2 analyzer. Acquisition of data for similar measurements is typically limited to engine speeds of below 1300 revolutions per minute (rpm) to allow full resolution of the sample through the analyzer that has an 8 ms finite response time. In order to sample in-cylinder CO2 at higher engine speeds, a skip-firing method is developed. By shutting off ignition intermittently during engine operation, the residual CO2 from the last firing cycle can be measured at significantly higher engine speeds. Comparison of RGF CO2 at low speeds for normal and skip-fire operation shows good correlation. This suggests that skip-firing is a suitable method for directly measuring internal exhaust gas recirculation up to at least 3000 rpm. The measurements obtained may provide a useful tool for validating internal exhaust gas recirculation models and could be used to calculate combustion air–fuel ratio from the CO and CO2 content of the burned gas. These are typically complicated parameters to predict due to the slow response time and sensitivity to hydrocarbons of wide-band oxygen sensors. A differing pattern of RGF change with increasing speed was seen between normal and skip-fire operation.

Joint Communication and Control for Small Underactuated USV Based on Mobile Computing Technology

To satisfy the requirement of the future ocean communication and maritime transportation, in this paper, an integrated space-air-ground-sea communication control system based on mobile computing technology is proposed to rescue a water container. Specifically, unmanned surface vehicle (USV), as a flexible and lightweight intelligent device deployment integration platform, is the main tool to move towards the water container. However, how to sense the real-time navigation status information of the USV, integrate the information, and eventually distribute it to the ground control center, is still a difficult point for us. To successfully rescue the water container, three aspects of research are needed: information collection of the USV, information fusion, and data distribution to the ground control center. For the information collection part, we mainly use nine-axis, ultrasonic, global positioning system (GPS), and ultra wide band (UWB) sensors to complete the information collection for the USV. For the information fusion part, we set up a computational model to solve it. The USV computational model in previous works is mainly based on large ships, ignoring the modeling of wind, wave, and current for small underactuated USV. We use the classical Nomoto model, combined with the actual any slight wind, wave, and current forces on the USV, and finally combined with the proportion integration differentiation (PID) algorithm to model the USV. For the data distribution to the ground control center part, we have set up a communication protocol for the USV so that it can communicate normally. In addition, we wrote a Browser/Server (B/S) architecture to enable the ground control center to communicate with the host computer. Finally, our proposed control and communication schemes are carried out on actual USV. The real experiments show that the proposed schemes can reduce the ship surge and satisfy the ship navigation.