Low Noise Figure of Cascaded LNA at 5.8GHz Using T-Matching Network for WiMAX Applications

This project presents the low Noise Figure (NF) cascaded Low Noise Amplifier (LNA) at 5.8GHz using T-matching network applicable for WiMAX application. The amplifier used FHX76LP Low Noise SuperHEMT FET. The LNA designed used T-matching network consisting of lump reactive element at the input and the output terminal. The cascaded LNA produced noise figure of 1.3 dB and forward gain of 36.8 dB. The input reflection (S11) and output return loss (S22) are -12.4 dB and -12.3 dB respectively. The bandwidth of the amplifier is more than 1.24 GHz. The input sensitivity is compliant with the IEEE 802.16 standards

Wideband 5.8 GHz Radio Frequency Amplifier with 3 dB Π- Network Attenuator Isolation

This paper presents a design of radio frequency amplifier (RFA), which operates at 5.8 GHz frequency for WiMAX application. The RFA designed used T-matching network consisting of lump reactive elements, 3 dB attenuator and microstrip line at the input and output impedance. The RFA developed in this project contribute a gain of 15.6 dB with overall noise figure of 2.4 dB. The overall measured bandwidth measures is 1.240 GHz with S parameters S11, S12 and S22 measured are -12.4 dB, -25.5 dB and -12.3 dB respectively. The RFA used FET transistor EPA018A from Excelics Semiconductor Inc

Retracted: Sensitivity enhancement of chemical sensor using aligned-gap split ring resonator

This article was withdrawn and retracted by the Journal of Fundamental and Applied Sciences and has been removed from AJOL at the request of the journal Editor in Chief and the organisers of the conference at which the articles were presented (www.iccmit.net). Please address any queries to [email protected]

Grain growth effects on magnetic properties of Ni0.6Zn0.4Fe2O4 material prepared using mechanically alloyed nanoparticles

The effect of grain growth via sintering temperature on some magnetic properties is reported in this research. Ni0.6Zn0.4Fe2O4 nanoparticles were mechanically alloyed for 6 h and the sintering process starting from 600 to 1200 °C with 25 °C increment with only one sample subjected to all sintering scheme. The resulting change in the material was observed after each sintering. Single phase has been formed at 600 °C and above and the intensity peaks increased with sintering temperature as well as crystallinity increment. The morphological studies showed grain size increment as the sintering temperature increased. Moreover, the density increased while the porosity decreased with increasing sintering temperature. The saturation induction, Bs increased with the increased of grain size. On the other hand, the coercivity-vs-grain size plot reveals the critical single-domain-to-multidomain grain size to be about ∼400 nm. The initial permeability, μi value was increased with grain size enhancement. The microstructural grain growth, as exposed for the first time by this research, is shown as a process of multiple activation energy barriers. Keywords: Mechanical alloying (MA), Magnetic properties, Single sample sintering (SSS), Ferrite

Wideband 5.8 GHz Radio Frequency Amplifier with 3 dB Π- Network Attenuator Isolation

This paper presents a design of radio frequency amplifier (RFA), which operates at 5.8 GHz frequency for WiMAX application. The RFA designed used T-matching network consisting of lump reactive elements, 3 dB attenuator and microstrip line at the input and output impedance. The RFA developed in this project contribute a gain of 15.6 dB with overall noise figure of 2.4 dB. The overall measured bandwidth measures is 1.240 GHz with S parameters S11, S12 and S22 measured are -12.4 dB, -25.5 dB and -12.3 dB respectively. The RFA used FET transistor EPA018A from Excelics Semiconductor Inc

Shape memory alloys actuated upper limb devices: A review

Recently, significant efforts have been made to develop prostheses, soft rehabilitation, and assistive devices that enhance the quality of life of limb amputees and the activities of daily living (ADL) of stroke patients. Therefore, this present study provides a general overview of the current prosthetic, assistive, and rehabilitative devices with a focus on actuators that provide actuation via shape-memory alloys (SMA). Shape-memory alloy (SMA)-based actuators are the subject of considerable research as they possess high force-to-weight ratio, quiet operation, muscular mobility, bio-compatibility, and accessible design options, all of which can potentially be used to develop inventive actuating systems. Several studies have examined the use of SMA-actuated devices in the medical and engineering industry. They have also, more recently, been used to develop soft robotic systems. This present review primarily focuses on the characterization, number, type of actuator, degrees of freedom (DOF), weight, cooling technique, control strategies, and applications as well as the advantages and disadvantages of plate, spring, and wire-based SMA actuators. Composite-based upper limb SMA actuators were also reviewed and compared in terms of the matrix, reinforcing materials, SMA configuration actuator dimensions, and manufacturing method as well as their advantages and disadvantages. The findings indicate that, in the last few years, more studies have examined developing novel intelligent materials with which to improve hand flexibility. Therefore, SMA materials have a promising future in the development of intelligent designs for hand-robots. They may also be used to improve control robustness as well as the accuracy of hand functions for ADL and effective rehabilitation