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Go to Editorial ManagerThe electrical and radio frequency (RF) characteristics of InAlGaN/GaN high electron mobility transistors (HEMTs) device with cap layer are presented in this work. In this work, Silicon carbide was used as a substrate for its excellent thermal conductivity. Here, the thermal model was used to investigate the simulation of temperature distribution at 300k. Moreover, the DC and AC performance characteristics of the device were investigated using Silvaco Atlas Technology Computer Aided Design TCAD simulator. The results showed that, the maximum obtained drain current that was 1.35 A. In addition to, the RF parameters were extracted. The cut-off frequency ft is (73 GHz), the maximum oscillation frequency fmax is (353 GHz), maximum stable gain (Gms) and maximum available gain (Gma) with a value of about (116 dB). The obtained results showed that the InAlGaN/GaN HEMT device based on SiC performance is suitable for microwave applications.
In this paper, a new compact coplanar antenna used for Radio frequency identification (FID) applications is presented. This antenna is operated at the resonant frequency of 2.45 GHz. The proposed antenna is designed on an epoxy substrate material type (FR-4) with small size of (40 × 28) mm2 in which the dielectric thickness (h) of 1.6 mm, relative permittivity (er) of 4.3 and tangent loss of 0.025. In this design the return loss is less than −10 dB in the frequency interval (2.12 − 2.84) GHz and the minimum value of return loss is -32 dB at resonant frequency. The maximum gain of the proposed antenna is 1.22 dB and the maximum directivity obtained is 2.27 dB. The patch and the ground plane of the proposed antenna are in the same surface. The proposed antenna has a wide bandwidth and omnidirectional radiation pattern with small size. The overall size of the compact antenna is (40 × 28 × 1.635) mm3. The Computer Simulation Technology (CST) microwave studio software is used for simulation and gets layout design.
In different modern and future wireless communication networks, a large number of low-power user equipment (UE) devices like Internet of Things, sensor terminals, and smart modules have to be supported over constrained power and bandwidth resources. Therefore, wireless-powered communication (WPC) is considered a promising technology for varied applications in which the energy harvesting (EH) from radio frequency radiations is exploited for data transmission. This requires efficient resource allocation schemes to optimize the performance of WPC and prolong the network lifetime. In this paper, harvest-then-transmit-based WP non-orthogonal multiple access (WP-NOMA) system is designed with time-split (TS) and power control (PC) allocation strategies. To evaluate the network performance, the sum rate and UEs’ rates expressions are derived considering power-domain NOMA with successive interference cancellation detection. For comparison purposes, the rate performance of the conventional WP orthogonal multiple access (WP-OMA) is derived also considering orthogonal frequency-division multiple access and time-division multiple access schemes. Intensive investigations are conducted to obtain the best TS and PC resource parameters that enable maximum EH for higher data transmission rates compared with the reference WP-OMA techniques. The achieved outcomes demonstrate the effectiveness of designed resource allocation approaches in terms of the realized sum rate, UE’s rate, rate region, and fairness without distressing the restricted power of far UEs.
The smart classroom is a fully automated classroom where repetitive tasks, including attendance registration, are automatically performed. Due to recent advances in artificial intelligence, traditional attendance registration methods have become challenging. These methods require significant time and effort to complete the process. Therefore, researchers have sought alternative ways to accomplish attendance registration. These methods include identification cards, radio frequency, or biometric systems. However, all of these methods have faced challenges in safety, accuracy, effort, time, and cost. The development of digital image processing techniques, specifically face recognition technology, has enabled automated attendance registration. Face recognition technology is considered the most suitable for this process due to its ability to recognize multiple faces simultaneously. This study developed an integrated attendance registration system based on the YOLOv7 algorithm, which extracts features and recognizes students’ faces using a specially collected database of 31 students from Mustansiriyah University. A comparative study was conducted by applying the YOLOv7 algorithm, a machine learning algorithm, and a combined machine learning and deep learning algorithm. The proposed method achieved an accuracy of up to 100%. A comparison with previous studies demonstrated that the proposed method is promising and reliable for automating attendance registration.
Radio frequency identification (RFID) technology is being used widely in the last few years. Its applications classifies into auto identification and data capturing issues. The purpose of this paper is to design and implement RFID active tags and reader using microcontroller ATmega328 and 433 MHz RF links. The paper also includes a proposed mutual authentication protocol between RFID reader and active tags with ownership transfer stage. Our protocol is a mutual authentication protocol with tag’s identifier updating mechanism. The updating mechanism has the purpose of providing forward security which is important in any authentication protocol to prevent the attackers from tracking the past transactions of the compromised tags. The proposed protocol gives the privacy and security against all famous attacks that RFID system subjected for due to the transfer of data through unsecure wireless channel, such as replay, denial of service, tracking and cloning attacks. It also ensures ownership privacy when the ownership of the tag moves to a new owner.
Radio frequency integrated circuits (RFICs) are widely used in wireless technology systems. Low-noise amplifiers, especially in the 5 GHz frequency range, are vital parts of contemporary wireless communication systems. Research on 5 GHz low-noise amplifiers aims to improve the performance of these amplifiers by addressing issues related to noise, gain, and power efficiency. Low-noise amplifiers are used in many different applications and are essential for developing more effective, efficient, and balanced wireless communication systems. The paper presents a wideband low-noise amplifier (LNA) implemented in a 5 GHz (Low-Noise Amplifier) for 5G Wi-Fi applications. It is driven by a 1.8 V supply. To increase the voltage gain and reduce the power consumption, the circuit has a common source layout and is optimized to reduce the noise figure. Single-stage common source decomposition and inductive source decomposition techniques are also used to match the circuit with the source impedance. Genetic algorithm is also used to optimize the circuit operation. The genetic algorithm has been shown to significantly reduce the noise in the low-noise amplifier circuit, which greatly improves the signal quality. The algorithm has increased the gain of the circuit, making it more sensitive to signals and enhancing its ability to process diverse signals. The proposed LNA showed a total current of 2 mA and a minimum noise figure of 1.107 dB with a high voltage gain of 21.86 dB and a power consumption of 3.6 mW. I expect the proposed LNA to be suitable for 5G Wi-Fi applications in the GHz band.
An essential component of every RF system’s reception chain is the Low-Noise Amplifier(LNA). The sensitivity and performance of subsequent stages in the receiver chain are significantly influenced by the LNA, which is the initial step. Creating an LNA requires carefully balancing trade-offs in order to have the best possible performance in terms of gain and noise characteristics. Achieving optimal functioning and efficiency in the radio frequency system requires finding the correct balance. This article presents the design of an LNA circuit at the lowest cost without adding components such as inductors, active components, or several stages, which increase the complexity of the circuit, consume power, and add additional noise, by controlling the lengths of the microstrip line, LNA circuit was created by ADS software, and add a matching circuit. At the operating frequency of 2.4 GHz, the suggested design achieved good results with a gain of 17.48dB, NF of 0.7dB, stability factor of 1.5dB, and S11-S22 (-41dB, -25dB) in that order.