Browsing by Subject "High power amplifier"

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    A 6-18 GHz GaN power amplifier MMIC with high gain and high output power density
    (IEEE, 2019) Sütbaş, Batuhan; Özipek, Ulaş; Gürdal, A.; Özbay, Ekmel
    A three-stage reactively-matched 6-18 GHz power amplifier MMIC design is presented. The design effort is focused on obtaining a low-loss output matching network for a high output power density. Active unit cells consist of an 8×125 μm transistor stabilized with a symmetrical parallel RC circuit. The wideband amplifier is fabricated using our in-house 0.25 μm GaN on SiC HEMT process. The fabrication technology details and overall device performance are reported. Experimental results show that the MMIC has a minimum gain of 22 dB and a maximum gain of 26.5 dB across the operation band. An average output power density higher than 3.3W/mm with an associated average power-added efficiency of 22.5% is achieved. The MMIC demonstrates output power greater than 9.5 W at the center frequency. This design is distinguished from recent studies with its low-ripple high gain and high output power density.
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    High power K-band GaN on SiC CPW monolithic power amplifier
    (IEEE, 2014-10) Cengiz, Ömer; Şen, Özlem; Özbay, Ekmel
    This paper presents a high power amplifier at K-band (20.2-21.2 GHz). The AlGaN/GaN CPW MMIC amplifier is realized with 0.25 μm HEMT process on 2-inch semi-insulating SiC substrate. The amplifier has a small signal gain over 20 dB for Vds=15V and measured output power of over 31 dBm at 20.2 Ghz. PAE of the amplifier is around 22% for desired frequency band. Initial radiation hardness tests indicate a suitable stability of the technology in space. © 2014 European Microwave Association.
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    Novel predistortion algorithm for OFDMA
    (IEEE, 2009) Ali, S.; Markarian, G.; Arıkan, Erdal
    The RF amplifier in a wireless communication system is usually non-linear in nature. If such an amplifier is used in OFDMA based systems, it will cause serious degradation. This degradation will be both in terms of the reduction in BER and the generation of out of band noise. In this paper we have worked on the linearization method of the amplifier. This work is on a hybrid methodology, in which estimation of the model is performed in frequency domain and compensation is performed in time domain. The downlink preamble of the IEEE802.16e system is used here for the estimation purpose. The results for the suppression of spectra are shown at the end.