Thisarticlepresentsthedesign and fabrication ofa high power amplifierbased onwilkinson power combiner. A 45W basic amplifier module isdesigned usinglaterally-diffused metal-oxide semiconductor (LDMOS) fieldeffect transistor (FET) PTFA260451E transistor. Wilkinson power combineris used to combine two input powers toproduce 90W of power. Theproposed power amplifier is researched, designed and optimized usingadvanced design system(ADS) software.Experimental results show that thegain is 11.5 dB greater than at 2.45-3.0GHz frequency band and achieving maximum power gain of 13.5dB at 2.65GHz centre frequency; output power increased to 49.3dBm; Power added efficiency of 62.1% and good impedances matching: input reflection coefficient (S11)<-10dB, output reflection coefficient (S22)<-15dB. The designed amplifier can be used for4G, 5G mobile communications andS-band satellite communication.

<span lang="EN-US">In the mobile communication via satellite, received systems are mounted on the mobile device such as ship, train, car or airplane. In order to receive continuous signals, received antenna system must be steered in both the azimuthal and elevation angle to track a satellite. This paper proposes the improved step-tracking algorithm using for mobile receiver system via satellite Vinasat I. This paper also presents the results of study, design and manufacture of the discrete-time controller system for the fast tracking of a satellite by applying an improved step tracking algorithm with fuzzy proportional integral derivative <span lang="EN-US">proportional integral derivative </span> controller. Simulated and experimental results indicate that the system performances obtain from applying the improved step tracking algorithm and the fuzzy controller was better than traditional control systems.</span>

<p>This paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals.</p>

<p>This paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals.</p>

Cameroon has several renewable energy sources, including solar, wind, and hydropower. With the liberalisation of the hydroelectric energy sector in Cameroon, rural communities are yet to feel the impact. Small Hydropower projects should have been developed to curb the acute shortage of electricity within these localities and beyond. This is not the case yet. It is in this respect that this study is carried out: to assess the hydropower potential of the Nkam Division and environs and propose sites for the development of hydroelectricity. Geographical Information System, Remote Sensing techniques, and hydrological models (HEC-HMS) were used. Grid analyses were carried out on the Digital Elevation Models (DEMs) using the Watershed Modelling System software to delineate the catchment basin with the sub-basins. Digital Soil and Land use data were obtained from the Harmonised World Soil Data and World Land use Data respectively, which together were used to calculate the Composite Curve Number in QGIS for the various sub-basins. The curve numbers together with other hydrological parameters were used to develop a HEC-HMS deterministic hydrologic model for the catchment basin. The resulting model was calibrated and validated in HEC-HMS, using precipitation data obtained from the localised Yabassi weather station and discharge values from a gauging station at Yabassi. The calibrated peak discharge produced an absolute error of 3.4% and a Nash-Sutcliffe value of 0.301. The hypsometric curve presents a hilly landscape, with 40% of the surface area having elevations of between 10 to 30 m, favouring the development of small scale hydro systems. The RETScreen software was used for the hydro-energy analyses and the estimated potential power, for a hydraulic head of 20 m, stood at 13,813 kW. The values of the Benefit-Cost Ratio value of 1.3 and the Net Present Value greater than zero show that the project is very practical and profitable. It follows that Small and Medium Run-of-River Hydropower Plants can be developed from the Wouri-Nkam Reach, the significant reach in the river network of the Catchment Basin, with an estimated compensation flow of 133.17m 3 /s for ecological continuity. The project will reduce about 27,064.8 tons of CO2 from the atmosphere.