Browsing by Subject "Amplifiers (Electronics)"

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    A ku-band phemt mmic high power amplifier design
    (2014) Değirmenci, Ahmet
    Power amplifiers are regarded as the one of the most important part of the radar and communication systems. In order to satisfy the system specifications, the power amplifiers must provide high output power and high efficiency at the same time. AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistors (PHEMT) provides significant advantages offering high output power and high gain at RF and microwave frequencies. Considering the electrical performance, cost and the reliability issues, pHEMT monolithic microwave integrated circuit (MMIC) high power amplifiers are one of the best alternatives at Ku-band frequencies (12-18 GHz portion of the electromagnetic spectrum in the microwave range of frequencies). In this thesis, a three-stage AlGaAs/InGaAs/GaAs pHEMT MMIC high power amplifier is developed which operates between 16-17.5 GHz. Based on 0.25 µm gate-length pHEMT process, the MMIC is fabricated on 4-mil thick wafer with the size of 5.5 x 5.7 mm2 . Under 8V drain voltage operation, 26.5-24 dB small signal gain, 10-W (40 dBm) continuous-wave mode output power at 3 dB compression with %25-30 drain efficiency is achieved when the base temperature is 85◦C.
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    ItemOpen Access
    A Two stage x-band low noise amplifier optimized for minimum noise application
    (2015) Yılmaz, Merve
    Low Noise Amplifiers (LNA) are used as the first stage of any radio frequency receiver or any sensitive application requiring detection of very small signals with the minimum possible additional noise in order to get maximum signal-to-noise ratio at the output which also provide large enough gain to supersede the noise added by the following stages. An X-Band two stage low noise amplifier operating in the 8.2-8.4 GHz frequency band with active bias network by using microstrip technology is studied. The first stage of the LNA is designed to minimize the noise figure and the second stage of the amplifier is designed to obtain the necessary gain. The input match is optimized for better noise figure and to obtain reasonable input coupling. Total gain is kept above a certain value in order not to degrade the total noise figure of the whole cascaded system. Stability is obtained without sacrificing the in-band gain. Agilent’s ADS tool is used to simulate and Altium Designer tool is used for PCB design. The measurement results are compared with simulation results and the comparison shows good agreement.