Significant progress has been achieved in making larger (2 inch) 4H-SiC substrates with much lower micropipe defect densities. With the recent availability of semi-insulating 4H-SiC substrates, the demonstration of impressive microwave power results have been made possible both in SiC MESFETs and in GaN/AlGaN HEMTs grown on these substrates. SiC MESFETs have achieved RF power densities of 4.6 W...

Stochastic excitation with a full-width-half-maximum bandwidth of 250 MHz was used to perform Fourier-transform (FT) high-field/high-frequency electron paramagnetic resonance (EPR) at 3.4T/95 GHz (W-band). Thereby, the required microwave peak power is reduced by a factor of tau(p)/T1 as compared to equivalent pulsed FT EPR in which the spin system with spin-lattice relaxation time T1 is excited...

seaweeds are the novel bioactive compounds resources with antioxidant activity. the aim of this study was to evaluate the efficacy of microwave radiation on antioxidant compounds extracted from red algae hypneahamulosa and optimal extraction conditions using response surface methodology (rsm).. independent variables were time (4,8,12 min), acetone/water concentration (50%,75% ,100% acetone) and...

wind power has been widely considered and utilized in recent years as one of the most promising renewable energy sources. in the current research study, aerodynamic analysis of the upwind three-bladed horizontal axis turbine is carried out using blade element momentum theory (bem), and a genetic algorithm (ga) is applied as an optimization method. output power generation is considered as an obj...

wind power has been widely considered and utilized in recent years as one of the most promising renewable energy sources. in the current research study, aerodynamic analysis of the upwind three-bladed horizontal axis turbine is carried out using blade element momentum theory (bem), and a genetic algorithm (ga) is applied as an optimization method. output power generation is considered as an obj...

| The rapid development of the RF power electronics requires the introduction of wide bandgap material due to its potential in high output power density, high operation voltage and high input impedance. GaN-based RF power devices have made substantial progresses in the last decade. This paper attempts to review the latest developments of the GaN HEMT technologies, including material growth, pro...

High Frequency Current Mode Class-D Amplifiers With High Output Power and Efficiency By Anthony Lawrence Long A 13 watt Current Mode Class-D (CMCD) with 60% efficiency is presented. This amplifier is the highest power switch mode microwave power amplifier reported to date. The CMCD architecture is an improvement over the Voltage Mode Class-D in that the parasitic reactance in the active device ...

In this paper, a multi-objective optimization method is implemented by using of genetic algorithm techniques in order to determine optimum configuration of solar chimney power plant. The objective function which is simultaneously considered in the analysis is output power of the plant. Output power of the system is maximized. Design parameters of the considered plant include collector radius (R...

Signal generation is one of the most critical problems in the microwave and millimeter-wave communication market. The demands of greater stability and low phase noise further increase complexity in the circuit design. Signal generation in the millimeter-wave bands can be realized either directly by an oscillator or by multiplication from a lower frequency. An effective solution is to multiply t...

Measurements of the active properties of a Dayem micro-bridge at X-band frequencies is described. The bridge was mounted in a microwave cavity designed to match the bridge properly and the microwave output from the cavity was detected using a sensitive X-band spectrometer. Micsowave power was detected from the freely running Josephson oscillations with the bridge dc-biased to emit at the receiv...