A Novel Coupling Mechanism for CSRRs as Near-Field Dielectric Sensors

This work proposes a novel coupling mechanism for a complementary split-ring resonator as a planar near-field microwave sensor for dielectric materials. The resonator is etched into the ground plane of a microstrip line. This mechanism is based on the inductive coupling synthesized by utilizing a via that connects the power plane of the microstrip line to the central island of the resonator. The proposed coupling makes the coupling capacitance between the transmission line and the resonator relatively small and insignificant compared to the capacitance of the resonator, making it more sensitive to changes in the dielectric constant of the materials under test. In addition, the coupling is no longer dependent solely on the capacitive coupling, which significantly reduces the coupling degradation caused by loading the resonator with dielectric materials, so the inductive coupling plays an important role in the proposed design. Therefore, the proposed coupling mechanism improves the sensitivity and enhances the coupling between the transmission line and the resonator. The sensor is evaluated for sensitivity, normalized resonance shift, and coupling factor using a full-wave numerical simulation. The sensitivity of the proposed sensor is 12% and 5.6% when detecting dielectric constants of 2 and 10, respectively. Compared to recent studies, the sensitivity improvement when detecting similar permittivity is 20% (1.32 times) and 9.8% (1.1 times). For verification, the proposed sensor is manufactured using PCB technology and is used to detect the presence of two dielectric laminates

Intelligent Sensing Using Multiple Sensors for Material Characterization

This paper presents a concept of an intelligent sensing technique based on modulating the frequency responses of microwave near-field sensors to characterize material parameters. The concept is based on the assumption that the physical parameters being extracted such as fluid concentration are constant over the range of frequency of the sensor. The modulation of the frequency response is based on the interactions between the material under test and multiple sensors. The concept is based on observing the responses of the sensors over a frequency wideband as vectors of many dimensions. The dimensions are then considered as the features for a neural network. With small datasets, the neural networks can produce highly accurate and generalized models. The concept is demonstrated by designing a microwave sensing system based on a two-port microstrip line exciting three-identical planar resonators. For experimental validation, the sensor is used to detect the concentration of a fluid material composed of two pure fluids. Very high accuracy is achieved.Applied Science, Faculty ofNon UBCReviewedFacult

A Patch Antenna with Enhanced Gain and Bandwidth for Sub-6 GHz and Sub-7 GHz 5G Wireless Applications

International audienceThis paper presents a novel microstrip patch antenna design using slots and parasitic strips to operate at the n77 (3.3–4.2 GHz)/n78 (3.3–3.8 GHz) band of sub-6 GHz and n96 (5.9–7.1 GHz) band of sub-7 GHz under 5G New Radio. The proposed antenna is simulated and fabricated using an FR-4 substrate with a relative permittivity of 4.3 and copper of 0.035 mm thickness for the ground and radiating planes. A conventional patch antenna with a slot is also designed and fabricated for comparison. A comprehensive analysis of both designs is carried out to prove the superiority of the proposed antenna over conventional dual-band patch antennas. The proposed antenna achieves a wider bandwidth of 160 MHz at 3.45 GHz and 220 MHz at 5.9 GHz, with gains of 3.83 dBi and 0.576 dBi, respectively, compared to the conventional patch antenna with gains of 2.83 dBi and 0.1 dBi at the two frequencies. Parametric studies are conducted to investigate the effect of the parasitic strip’s width and length on antenna performance. The results of this study have significant implications for the deployment of high-gain compact patch antennas for sub-6 GHz and sub-7 GHz 5G wireless communications and demonstrate the potential of the proposed design to enhance performance and efficiency in these frequency bands

A Compact 2.4 GHz L-Shaped Microstrip Patch Antenna for ISM-Band Internet of Things (IoT) Applications

Wireless communication technology integration is necessary for Internet of Things (IoT)-based applications to make their data easily accessible. This study proposes a new, portable L-shaped microstrip patch antenna with enhanced gain for IoT 2.4 GHz Industrial, Scientific, and Medical (ISM) applications. The overall dimensions of the antenna are 28 mm × 21 mm × 1.6 mm (0.22λo × 0.17λo × 0.013λo, with respect to the lowest frequency). The antenna design is simply comprised of an L-shape strip line, with a full ground applied in the back side and integrated with a tiny rectangular slot. According to investigations, the developed antenna is more efficient and has a greater gain than conventional antennas. The flexibility of the antenna’s matching impedance and performance are investigated through several parametric simulations. Results indicate that the gain and efficiency can be enhanced through modifying the rectangular back slot in conjunction with fine-tuning the front L-shaped patch. The finalized antenna operates at 2.4 GHz with a 98% radiation efficiency and peak gains of 2.09 dBi (measured) and 1.95 dBi (simulated). The performance of the simulation and measurement are found to be in good agreement. Based on the performance that was achieved, the developed L-shaped antenna can be used in a variety of 2.4 GHz ISM bands and IoT application environments, especially for indoor localization estimation scenarios, such as smart offices and houses, and fourth-generation (4G) wireless communications applications due to its small size and high fractional bandwidth

Mammography using low-frequency electromagnetic fields with deep learning

Abstract In this paper, a novel technique for detecting female breast anomalous tissues is presented and validated through numerical simulations. The technique, to a high degree, resembles X-ray mammography; however, instead of using X-rays for obtaining images of the breast, low-frequency electromagnetic fields are leveraged. To capture breast impressions, a metasurface, which can be thought of as analogous to X-rays film, has been employed. To achieve deep and sufficient penetration within the breast tissues, the source of excitation is a simple narrow-band dipole antenna operating at 200 MHz. The metasurface is designed to operate at the same frequency. The detection mechanism is based on comparing the impressions obtained from the breast under examination to the reference case (healthy breasts) using machine learning techniques. Using this system, not only would it be possible to detect tumors (benign or malignant), but one can also determine the location and size of the tumors. Remarkably, deep learning models were found to achieve very high classification accuracy

Electromagnetic Characteristics Interpretation of Partial Discharge Phenomena at Variable Distance in High-Voltage Systems

International audienceInsulations at high voltage (HV), whether in HVAC or HVDC systems, often encounter an unwanted partial discharge (PD) phenomenon. PD poses a potential danger to HV insulation and can eventually lead to equipment failures. Out of all electromagnetic (EM) sensing techniques for PD diagnosis, the ultra-high frequency (UHF) method has gained popularity as it allows non-invasive detection at varying distances from PD defects. The EM behavior of PD is significantly affected by the distance between a PD defect and a UHF sensor. This effect varies for different PD defects under different HV conditions. So, considering variable distances, there is a need to analyze EM characteristics of different PD phenomena at different HV conditions. To the best of our knowledge, for the first time, electromagnetic characteristics of different PD defects are experimentally investigated in this work by capturing PD signals from variable distances in both HVAC and HVDC conditions and individually validating their characteristics with EM radiation theories. For wirelessly capturing PD signals, a new UHF sensor is designed with a modified elliptical-shaped antenna on an FR-4 material. The fabricated sensor provides an average realized gain of about 3.66 dBi while covering more than 97% of the total UHF range for PD detection. Applying HVAC, HVDC+, and HVDC–, PDs from three defects (surface, void, free wire) are captured from 1–4 m distances. Interpreted results show that EM radiation in the UHF range from a PD defect is heavily impacted by its detection distance and defect formation despite applied voltage and other conditions being unchanged for the defect. This investigation is particularly beneficial to the variable distance-based PD diagnosis, such as PD localization and handheld PD detection at HVAC/HVDC open substations

Electromagnetic Characteristics Interpretation of Partial Discharge Phenomena at Variable Distance in High-Voltage Systems

International audienceInsulations at high voltage (HV), whether in HVAC or HVDC systems, often encounter an unwanted partial discharge (PD) phenomenon. PD poses a potential danger to HV insulation and can eventually lead to equipment failures. Out of all electromagnetic (EM) sensing techniques for PD diagnosis, the ultra-high frequency (UHF) method has gained popularity as it allows non-invasive detection at varying distances from PD defects. The EM behavior of PD is significantly affected by the distance between a PD defect and a UHF sensor. This effect varies for different PD defects under different HV conditions. So, considering variable distances, there is a need to analyze EM characteristics of different PD phenomena at different HV conditions. To the best of our knowledge, for the first time, electromagnetic characteristics of different PD defects are experimentally investigated in this work by capturing PD signals from variable distances in both HVAC and HVDC conditions and individually validating their characteristics with EM radiation theories. For wirelessly capturing PD signals, a new UHF sensor is designed with a modified elliptical-shaped antenna on an FR-4 material. The fabricated sensor provides an average realized gain of about 3.66 dBi while covering more than 97% of the total UHF range for PD detection. Applying HVAC, HVDC+, and HVDC–, PDs from three defects (surface, void, free wire) are captured from 1–4 m distances. Interpreted results show that EM radiation in the UHF range from a PD defect is heavily impacted by its detection distance and defect formation despite applied voltage and other conditions being unchanged for the defect. This investigation is particularly beneficial to the variable distance-based PD diagnosis, such as PD localization and handheld PD detection at HVAC/HVDC open substations