Detection Power Research Articles

A wide locking range injection‐locked frequency divider with an auto‐adjusted injection bias

AbstractThis paper presents a Ku‐band divide‐by‐2 direct injection‐locked frequency divider (ILFD) with a wide locking range (LR) and high input sensitivity. The proposed ILFD incorporates an auto‐adjusted injection bias that uses a power detector (PD) to convert the power of the injected signal to a DC voltage. The bias voltage of the injection transistor is then auto‐adjusted in response to the output of the PD. The proposed ILFD employs a 2‐bit switched capacitor array to further enhance the entire LR. Implemented in a 65‐nm CMOS process, the experimental results show that the proposed ILFD achieves an LR of 62.3% (10.5–20 GHz) and 51.2% (11.2–18.9 GHz) at 0 and −10 dBm injection power, respectively. The proposed ILFD consumes 3.6 mW from a 0.6 V supply, and the core area is 0.067 mm2.

A Metamaterial Energy Power Detector Based on Electromagnetic Energy Harvesting Technology

A Metamaterial Energy Power Detector Based on Electromagnetic Energy Harvesting Technology

Experimental study of a temperature measurement system for an overhead power line using sensors based on TFBG

This article presents the use of an inclined fiber sensor Bragg grid to control the extension of wires in overhead lines. An aspect of the technological novelty of the project is the development of an innovative optoelectronic system for monitoring and diagnosing the condition of building structures based on a combination of conventional Bragg gratings. The lighting power sensor is installed directly on the controlled transmission of the power line in the form of fittings with a copper plate. A photosensitive multimode optical fiber is attached to the copper plate, at the end of which an inclined fiber Bragg grating is fixed, connected to a multimode optical fiber using a fiber-optic connector through an optical connector. An ultraviolet excimer laser and a light power detector are connected to a fiber-optic connector. The study showed that by selecting the appropriate mechanical parameters of the extension transformer, taking into account the optical parameters of the sensor, and using a special filter, the optical-mechanical system can be configured in the required range to control the sagging of the overhead line wire. During measurements to simulate the operation of a power line wire, the temperature was forced to vary in the range of 10-60°C. This led to the lengthening of the test wire from 38.987 m to 49.275 m; the error was within 4%. The deflection range depends on the distance between the supports, the type of wire, and its actual length in the span, which actually determines the deflection.

Effects of Neutron Flux Distribution and Control Rod Shadowing on Control Rod Calibrations in the Oregon State TRIGA® Reactor

Control rod calibration experiment results for the Oregon State TRIGA® Reactor (OSTR) immediately following LEU conversion in 2008, and MCNP® 5 predicted rod worths from the 2008 LEU Conversion Safety Analysis Report (CSAR) are discussed. The reactivity worth of the four OSTR control rods is measured using the rod-pull method. Reactor power and period measurements in this method rely on the fission chamber power detector on the north side of the reflector. It is proposed that the location of the fission chamber and the neutron flux distribution in the core may result in an inaccurate reactor period measurement due to the asymmetry of the neutron flux distribution in the OSTR core. The asymmetry of the flux is believed to be more pronounced during super-criticality, resulting in errors in the time-of-power-rise measurements. As a result, control rod calibration experiments may under-predict or over-predict the reactivity worth of certain control rods. A time-independent Monte–Carlo method for the quantification of these effects is presented. Thermal flux maps at the core axial mid-plane are obtained from the model to inform discrepancies between predicted and observed results.

Power Detector Performance and Placement Effects on Measurement Accuracy in Sampled-Network Reflectometry

Power Detector Performance and Placement Effects on Measurement Accuracy in Sampled-Network Reflectometry

Analysis of fluctuations in ex-core neutron detector signal in Krško NPP during an earthquake

During an earthquake on December 29th 2020, the Krško NPP automatically shutdown due to the trigger of the negative neutron flux rate signal on the power range nuclear instrumentation. From the time course of the detector signal, it can be concluded that the fluctuation in the detector signal may have been caused by the mechanical movement of the ex-core neutron detectors or the pressure vessel components rather than the actual change in reactor power. The objective of the analysis was to evaluate the sensitivity of the neutron flux at the ex-core detector position, if the detector is moved in the radial or axial direction. In addition, the effect of the core barrel movement and core inside the baffle movement in the radial direction were analysed. The analysis is complemented by the calculation of the thermal and total neutron flux gradient in radial, axial and azimuthal directions. The Monte Carlo particle transport code MCNP was used to study the changes in the response of the ex-core detector for the above-mentioned scenarios. Power and intermediate-range detectors were analysed separately, because they are designed differently, positioned at different locations, and have different response characteristics. It was found that the movement of the power range ex-core detector has a negligible effect on the value of the thermal neutron flux in the active part of the detector. However, the radial movement of the intermediate-range detector by 5 cm results in 7%–8% change in the thermal neutron flux in the active part of the intermediate-range detector. The analysis continued with an evaluation of the effects of moving the entire core barrel on the ex-core detector response. It was estimated that the 2 mm core barrel radial oscillation results in ∼4% deviation in the power and intermediate-range detector signal. The movement of the reactor core inside baffle can contribute ∼6% deviation in the ex-core neutron detector signal. The analysis showed that the mechanical movement of ex-core neutron detectors cannot explain the fluctuations in the ex-core detector signal. However, combined core barrel and reactor core inside baffle oscillations could be a probable reason for the observed fluctuations in the ex-core detector signal during an earthquake.

The Design of a Wide-Dynamic-Range and High-Linearity RMS Power Detector for mm-Wave Applications in 65 nm CMOS

In this paper, a wide dynamic range RMS power detector with an operating frequency from 24 GHz to 35 GHz mm-wave frequency is presented. The power detector is fabricated in a 65 nm CMOS process. It is composed of a power detector unit, a radio frequency signal attenuator and a linear proportional voltage adder. The equalization technique is used to achieve a good linearity performance. The input dynamic range of the power detector is expanded by using one radio frequency signal attenuator and five power detector units. The simulation results show the slope of VOUT versus input power remaining constant at around 0.06 V/dBm when the input signal power varies from −10 dBm to 10 dBm. The difference in output voltage varies by only 0.03 V when the input power varies from −10 to 0 dBm and 0 to 10 dBm. These all indicate that the proposed power detector achieves a good linearity performance. The measured results also show that the proposed power detector achieves a wide dynamic range and a high linearity performance from −10 dBm to 10 dBm. The detectable dynamic range is enhanced by 3.3 times compared to that achieved when only using one single power detector unit, while it only consumes about 0.75 mW under a 1.2 V supply voltage.

Development of an Optoelectronic System for Recording and Processing Signals From Fiber-optic Sensors

Natural disasters, in particular earthquakes, can damage bridges, tunnels, dams, high-rise buildings, railways, oil platforms, buildings, and pipelines with catastrophic humanitarian, social, economic, and environmental consequences. Thus, automatic assessment of damage to industrial and civil construction structures after an earthquake in real-time or on request is necessary for early emergency response, effective preparation of rescue plans, and mitigation of these catastrophic consequences. The article presents the use of a system of distributed fiber-optic sensors based on Bragg fiber arrays, which will allow periodic measurements and monitoring of the condition of structures, assessing trends in its technical condition and thereby facilitating the identification of possible threats. The given research presents assembling and testing optoelectronic systems to record and process signals from fiber-optic sensors. The main optoelectronic systems to record and process the signals from fiber-optic sensors are light source controllers and optical power detectors. There was an assembled controller diagram, which apart from the light source includes the current source for its adequate operation, as well as the systems necessary for stabilizing its working point. The scheme was modeled for specifying nominal and maximum operation criteria. Construction has been designed in a way, that the light source controller includes structures of the current regulation and stabilization SLED (super luminescent diode) and temperature stabilization. Apart from that, there was assembled the microsystem of the optical power detector additionally to the light detector, which includes the microsystems of intensification and filtration of the signal measured, processing analog data into digital form, and microcontroller, used for preliminary data analysis. Data of optoelectronic systems diagram to record and process the signals from fiber-optic sensors has high response speed, low noise level, and sufficient progress. type your abstract here.

Exploration of high-speed 3.0 THz imaging with a 65 nm CMOS process

This paper describes a promising route for the exploration and development of 3.0 THz sensing and imaging with FET-based power detectors in a standard 65 nm CMOS process. Based on the plasma-wave theory proposed by Dyakonov and Shur, we designed high-responsivity and low-noise multiple detectors for monitoring a pulse-mode 3.0 THz quantum cascade laser (QCL). Furthermore, we present a fully integrated high-speed 32 × 32-pixel 3.0 THz CMOS image sensor (CIS). The full CIS measures 2.81 × 5.39 mm2 and achieves a 423 V/W responsivity (Rv) and a 5.3 nW integral noise equivalent power (NEP) at room temperature. In experiments, we demonstrate a testing speed reaching 319 fps under continuous-wave (CW) illumination of a 3.0 THz QCL. The results indicate that our terahertz CIS has excellent potential in cost-effective and commercial THz imaging and material detection.

A 29–31-GHz, 0.4-dB Amplitude Error and 1° Phase Error Beamforming IC and 20-dB Dynamic Range Power Detector for SatCom Phased Arrays

A 29–31-GHz, 0.4-dB Amplitude Error and 1° Phase Error Beamforming IC and 20-dB Dynamic Range Power Detector for SatCom Phased Arrays

Metasurface-Based Microwave Power Detector for Polarization Angle Detection

Metasurface-Based Microwave Power Detector for Polarization Angle Detection

Two-dimensional tellurium-based diodes for RF applications

The research of two-dimensional (2D) Tellurium (Te) or tellurene is thriving to address current challenges in emerging thin-film electronic and optoelectronic devices. However, the study of 2D-Te-based devices for high-frequency applications is still lacking in the literature. This work presents a comprehensive study of two types of radio frequency (RF) diodes based on 2D-Te flakes and exploits their distinct properties in two RF applications. First, a metal-insulator-semiconductor (MIS) structure is employed as a nonlinear device in a passive RF mixer, where the achieved conversion loss at 2.5 GHz and 5 GHz is as low as 24 dB and 29 dB, respectively. Then, a metal-semiconductor (MS) diode is tested as a zero-bias millimeter-wave power detector and reaches an outstanding linear-in-dB dynamic range over 40 dB, while having voltage responsivities as high as 257 V ⋅ W−1 at 1 GHz (up to 1 V detected output voltage) and 47 V ⋅ W−1 at 2.5 GHz (up to 0.26 V detected output voltage). These results show superior performance compared to other 2D material-based devices in a much more mature technological phase. Thus, the authors believe that this work demonstrates the potential of 2D-Te as a promising material for devices in emerging high-frequency electronics.

Design of power and phase feedback control system for ion cyclotron resonance heating in the Experimental Advanced Superconducting Tokamak

Ion cyclotron range of frequency (ICRF) heating system is an important auxiliary heating method in the experimental Advanced Superconducting Tokamak (EAST). In EAST, several megawatts of power are transmitted with coaxial transmission lines and coupled to the plasma. For the long pulse and high power operation of the ICRF waves heating system, it is very important to effectively control the power and initial phase of the ICRF signals. In this paper, a power and phase feedback control system is described based on field programmable gate array (FPGA) devices, which can realize complicated algorithms with the advantages of fast running and high reliability. The transmitted power and antenna phase are measured by a power and phase detector and digitized. The power and phase feedback control algorithms is designed to achieve the target power and antenna phase. The power feedback control system was tested on a dummy load and during plasma experiments. Test results confirm that the feedback control system can precisely control ICRF power and antenna phase and is robust during plasma variations.

Unsupervised Multitaper Spectral Method for Identifying REM Sleep in Intracranial EEG Recordings Lacking EOG/EMG Data.

A large number of human intracranial EEG (iEEG) recordings have been collected for clinical purposes, in institutions all over the world, but the vast majority of these are unaccompanied by EOG and EMG recordings which are required to separate Wake episodes from REM sleep using accepted methods. In order to make full use of this extremely valuable data, an accurate method of classifying sleep from iEEG recordings alone is required. Existing methods of sleep scoring using only iEEG recordings accurately classify all stages of sleep, with the exception that wake (W) and rapid-eye movement (REM) sleep are not well distinguished. A novel multitaper (Wake vs. REM) alpha-rhythm classifier is developed by generalizing K-means clustering for use with multitaper spectral eigencoefficients. The performance of this unsupervised method is assessed on eight subjects exhibiting normal sleep architecture in a hold-out analysis and is compared against a classical power detector. The proposed multitaper classifier correctly identifies 36±6 min of REM in one night of recorded sleep, while incorrectly labeling less than 10% of all labeled 30 s epochs for all but one subject (human rater reliability is estimated to be near 80%), and outperforms the equivalent statistical-power classical test. Hold-out analysis indicates that when using one night's worth of data, an accurate generalization of the method on new data is likely. For the purpose of studying sleep, the introduced multitaper alpha-rhythm classifier further paves the way to making available a large quantity of otherwise unusable IEEG data.

Norm‐based spectrum sensing for cognitive radios under generalised Gaussian noise

AbstractCognitive radio (CR) systems are configured to dynamically assess the spectrum utilisation and contribute towards an improved spectrum efficiency. Hence, accurate detection of the incumbent signal in a given channel, popularly known as spectrum sensing (SS), is essential for CR. Here, in the domain of SS, the authors introduce a new goodness‐of‐fit test (GoFT) founded on p‐norm of the observations at the receiver node. To capture the heavy‐tailed nature of noise distribution in practical communication channels, the authors utilise generalised Gaussian distribution (GGD) as a noise model. A novel p‐norm detector (PND) and a geometric power detector (GPD) is proposed and corresponding probability density function (PDF) under GGD is derived. Via Monte Carlo simulations, the authors show a match of the derived PDFs with the simulation results. Using Neyman‐Pearson framework the performances of PND and GPD are compared with an existing differential entropy detector (DED), the well‐known energy detector (ED) and joint correlation and energy detector (CED) under GGD noise model. Evaluation of proposed PND and GPD utilising Monte Carlo simulations indicate a superior performance. Further, the experiments employing real‐world data establish superiority of the proposed detectors as compared to existing techniques. The authors derive and implement an optimised threshold for PND, providing further improvement in performance.

Sequential detection of transient signal by moving likelihood ratio statistic in an exponential family

ABSTRACT We first consider the sequential detection of transient signals by generalizing the moving average chart to exponential family and study the false detection probability (FDP) and power of detection (POD) in the steady state. Then windowed adjusted signed (or modified directed) likelihood ratio chart is studied by treating it as approximate normal random variable. In the multi-parameter exponential family, the detection of the transient change of one of the canonical parameters or a function of canonical parameters is considered by using the generalized adjusted signed likelihood ratio chart. Comparisons with window restricted CUSUM and Shiryayev-Roberts (S-R) procedures show that the generalized signed likelihood ratio chart performs quite well. Several important examples including the mean or variance change under normal model and a real-time example are used for illustration.

On-Chip Optical Waveguide Visible-Light Power Detector Based on Photothermal Effect of PPy/SU-8 Photopolymer

In this work, an all-optical on-chip polymer waveguide visible-light power detector is proposed based on photothermal effect of polypyrrole (PPy) nanoparticles. PPy/SU-8 waveguide material is prepared and the strong optical absorption of the photopolymer in the visible-light region is beneficial for efficient photothermal energy conversion. The photothermal characteristics of PPy/SU-8 are analyzed, and through selective absorption specificity of the PPy/SU-8 photopolymer in Vis-NIR region, the performances of the multimode interference (MMI) waveguide device by thermo-optic (TO) tuning are simulated. The photothermal energy conversion coefficient of the PPy/SU-8 waveguide is obtained as 2.5 K/mW. The actual sensitivity of the on-chip light power detector is measured as 2.3 nm/mW. This technique could be used to achieve ultra-compact on-chip all-optical detectors in future.

Study on Time-frequency Imaging of Ultrasonic Detection with Phase Shifted Fiber Bragg Grating Sensing

Abstract The influence of the wavelength difference between the laser source and the phase-shifted fiber Bragg grating (PS-FBG) on the intensity of the power demodulation system based on an adjustable laser source was studied experimentally, and the optimum of the output laser wavelength was determined. Then, the research on time-frequency imaging damage identification based on smooth pseudo-Wigner-Ville distribution was carried out. The Time of Flight of the acoustic wave signal was calculated and time compensation was made according to the Wigner-Ville distribution and the Lamb wave dispersion curve. The ultrasonic waves before and after damage were measured with spatially arranged PS-FBGs. The difference signals were processed in a window, and then the time-frequency energy of the normalized difference signal was imaged to assess the damage detection and location. Although the mode and group velocity of ultrasound measured by each fiber grating were different, the accurate location and identification of artificial damage in an aluminum alloy plate was realized by using only three PS-FBGs and a smooth Wigner time-frequency imaging method.

Speeding axion haloscope experiments using heterodyne-variance-based detection with a power meter

We describe a new axion search method based on measuring the variance in the interference of the axion signal using injected photons with a power detector. The need for a linear amplifier is eliminated by putting a strong signal into the microwave cavity, to acquire not only the power excess but also measure the variance of the output power. The interference of the external photons with the axion to photon converted signal greatly enhances the variance at the particular axion frequency, providing evidence of its existence. This method has an advantage in that it can always obtain sensitivity near the quantum noise limit even for a power detector with high dark count rate. We describe the basic concept of this method both analytically and numerically, and we show experimental results using a simple demonstration circuit.

Time-Switching Symmetric Transmitter Array to Increase Sweet Region for Far-Field Wireless Power Transmission Under Receiver Rotation and Location Variation

For wireless power transfer using linear-polarized transmitter (TX) and receiver antennas, the rotation and movement of receiving antenna cause received power variation. The received power pattern is proposed to describe the received power variation from a specific TX antenna under receiver rotation. By placing the peak of the received power pattern of additional TX antennas in null directions of the previous TX antenna, received power variation due to rotation can be compensated. With symmetrically placed TX antennas, the power variation due to location variation can be compensated. This article proposes a time-switching symmetric transmitting array combining both techniques to increase the sweet region for far-field wireless power transfer under rotation and location variation. A sweet region is an area in the 2-D case or volume in the 3-D case, which is defined as an area or a volume inside the TX array that can get guaranteed minimum received power under rotation. The received power calculation using the Friis equation with short dipole antenna pattern shows that a symmetric TX array can achieve a larger sweet region than an asymmetric TX array under the same total transmitted power. The efficiency for the receiver at the origin is 1/2 at the 2-D case and 1/3 at the 3-D case. In the experiment, a linear-polarized TX array at 915 MHz with monopole receiver antenna and power detector is used as the receiver to measure received power under rotation and location variation. Measurement results at 2-D and 3-D cases confirm the received power level predicted by calculation using the Friis equation. The power budget calculation for wirelessly powering a sensor module attached on a bee inside a beehive using the proposed 3-D TX array shows that it is feasible to deliver sufficient power to the sensor module regardless of the orientation and location of the bee inside the beehive.