scholarly journals Properties and Performance Verification on Magnetite Polydimethylsiloxane Graphene Array Microwave Sensor

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3254
Author(s):  
Mohd Aminudin Jamlos ◽  
Mohd Faizal Jamlos ◽  
Azri Alias ◽  
Mohamad Shaiful Abdul Karim ◽  
Wan Azani Mustafa ◽  
...  
Keyword(s):  
Loss Tangent ◽  
Transmission Lines ◽  
Detection System ◽  
Wide Band ◽  
High Gain ◽  
Maximum Energy ◽  
Low Loss ◽  
Band Frequency ◽  
Microwave Sensor ◽  
Low Permittivity

This paper investigates the use of a Magnetite Polydimethylsiloxane (PDMS) Graphene array sensor in ultra-wide band (UWB) spectrum for microwave imaging applications operated within 4.0–8.0 GHz. The proposed array microwave sensor comprises a Graphene array radiating patch, as well as ground and transmission lines with a substrate of Magnetite PDMS-Ferrite, which is fed by 50 Ω coaxial ports. The Magnetite PDMS substrate associated with low permittivity and low loss tangent realized bandwidth enhancement and the high conductivity of graphene, contributing to a high gain of the UWB array antenna. The combination of 30% (ferrite) and 70% (PDMS) as the sensor’s substrate resulted in low permittivity as well as a low loss tangent of 2.6 and 0.01, respectively. The sensor radiated within the UWB band frequency of 2.2–11.2 (GHz) with great energy emitted in the range of 3.5–15.7 dB. Maximum energy of 15.7 dB with 90 × 45 (mm) in small size realized the integration of the sensor for a microwave detection system. The material components of sensor could be implemented for solar panel.

scholarly journals A Wide-Band High-Gain Doherty Power Amplifier With Class-AB HEMT Amplifiers

2021 ◽  
Author(s):  
Pouya Jahanian ◽  
Azadeh Norouzi Kangarshahi
Keyword(s):  
Power Amplifier ◽  
Transmission Lines ◽  
Average Power ◽  
Wide Band ◽  
High Gain ◽  
Input Power ◽  
Power Ratio ◽  
Class Ab ◽  
Power Added Efficiency ◽  
Doherty Power Amplifier

Abstract In this paper, an attempt has been made to design a Doherty power amplifier (DPA) with high-gain and wide-band. For this purpose, two peak amplifiers are used to improve the performance of the main amplifier. Main and auxiliary amplifiers with the same structure to the class-AB type and by using micro-strip lines in place of input/output and load matching networks, transmission lines and inductors of drain and gate, that minimize the losses in the DPA. The current DPA is implemented with GaN_HEMT_CLF1G0530_100v transistor and Rogers4003 substrate, which for 1GHz frequency in 0.5-1.5GHz bandwidth will be able to be at P-1dB point (this point, input power as 30dBm and output power as 47.98dBm) increase Drain efficiency and Power added efficiency (PAE) to 81.95% and 80.73%, respectively. The DPA helps to expand the back-off region and extend the linearity region, so the Peak to average power ratio (PAPR) will be 5.21dB and the Adjacent channel power ratio (ACPR) as 58.7dBc. A gain of 17.06-17.92dB was also obtained, which is significant compared to the results of similar samples.

scholarly journals The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3230
Author(s):  
Theeranuch Nachaithong ◽  
Narong Chanlek ◽  
Pairot Moontragoon ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Loss Tangent ◽  
Barrier Layer ◽  
Dielectric Response ◽  
High Resistivity ◽  
Low Loss ◽  
Rutile Tio2 ◽  
Complex Defect ◽  
Very High ◽  
Co Doped

(Co, Nb) co-doped rutile TiO2 (CoNTO) nanoparticles with low dopant concentrations were prepared using a wet chemistry method. A pure rutile TiO2 phase with a dense microstructure and homogeneous dispersion of the dopants was obtained. By co-doping rutile TiO2 with 0.5 at.% (Co, Nb), a very high dielectric permittivity of ε′ » 36,105 and a low loss tangent of tanδ » 0.04 were achieved. The sample–electrode contact and resistive outer-surface layer (surface barrier layer capacitor) have a significant impact on the dielectric response in the CoNTO ceramics. The density functional theory calculation shows that the 2Co atoms are located near the oxygen vacancy, creating a triangle-shaped 2CoVoTi complex defect. On the other hand, the substitution of TiO2 with Nb atoms can form a diamond-shaped 2Nb2Ti complex defect. These two types of complex defects are far away from each other. Therefore, the electron-pinned defect dipoles cannot be considered the primary origins of the dielectric response in the CoNTO ceramics. Impedance spectroscopy shows that the CoNTO ceramics are electrically heterogeneous, comprised of insulating and semiconducting regions. Thus, the dielectric properties of the CoNTO ceramics are attributed to the interfacial polarization at the internal insulating layers with very high resistivity, giving rise to a low loss tangent.

A Compact and Configurable Gasoline Detection System Using a Microwave Sensor

2021 ◽  
pp. 1-1
Author(s):  
Chong Hyun Lee ◽  
Yoon-Sang Jeong ◽  
Hina Ashraf
Keyword(s):  
Detection System ◽  
Microwave Sensor

Breath air measurement using wide-band frequency tuning IR laser photo-acoustic spectroscopy

2016 ◽  
Author(s):  
Yury V. Kistenev ◽  
Alexey V. Borisov ◽  
Dmitry A. Kuzmin ◽  
Anna A. Bulanova ◽  
Andrey A. Boyko ◽  
...  
Keyword(s):  
Frequency Tuning ◽  
Wide Band ◽  
Band Frequency ◽  
Ir Laser ◽  
Acoustic Spectroscopy ◽  
Photo Acoustic Spectroscopy

scholarly journals A 60 GHz fully differential LNA in 90 nm CMOS technology

2013 ◽  
Vol 6 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Andrea Malignaggi ◽  
Amin Hamidian ◽  
Georg Boeck
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Transmission Lines ◽  
Noise Figure ◽  
Design Procedure ◽  
Cmos Technology ◽  
High Gain ◽  
Low Noise ◽  
60 Ghz ◽  
Fully Differential

The present paper presents a fully differential 60 GHz four stages low-noise amplifier for wireless applications. The amplifier has been optimized for low-noise, high-gain, and low-power consumption, and implemented in a 90 nm low-power CMOS technology. Matching and common-mode rejection networks have been realized using shielded coplanar transmission lines. The amplifier achieves a peak small-signal gain of 21.3 dB and an average noise figure of 5.4 dB along with power consumption of 30 mW and occupying only 0.38 mm2pads included. The detailed design procedure and the achieved measurement results are presented in this work.

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