Browsing by Subject "GHz frequencies"

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    Design of high power S-band GaN MMIC power amplifiers for WiMAX applications
    (IEEE, 2011) Cengiz, Ömer; Kelekçi, Özgür; Arıkan, Galip Orkun; Özbay, Ekmel; Palamutçuoǧullari O.
    This paper reports two different S band GaN MMIC PA designs for WiMAX applications. First PA has a 42.6 dBm output power with a 55%PAE @ 3.5 GHz and 16 dB small signal gain in the 3.2-3.8 GHz frequency range. When two of these MMICs were combined by using off-chip Lange Couplers, 45.3 dBm output power with a 45%PAE @3.5Ghz and 16 dB small signal gain were obtained with less than 0.2 dB gain ripple in the 3.3-3.8 GHz frequency range. © 2011 IEEE.
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    Radiation properties and coupling analysis of a metamaterial based, dual polarization, dual band, multiple split ring resonator antenna
    (Taylor and Francis, 2012-04-03) Alici, K. B.; Serebryannikov, A. E.; Özbay, Ekmel
    We demonstrate an electrically small antenna that operates at two modes, which correspond to two orthogonal polarizations. The antenna was single fed and composed of perpendicularly placed metamaterial elements and a monopole. One of the metamaterial elements was a multi split ring resonator (MSRR), and the other one was a split ring resonator (SRR). The elements' physical sizes were the same while the electrical sizes differed nearly by 1 GHz. This variety resulted in the dual mode operation at the 4.72 GHz and 5.76 GHz frequencies. When the antenna operated in the MSRR mode at 4.72 GHz for one polarization, it simultaneously operated for the SRR mode at 5.76 GHz, but for the perpendicular polarization. The efficiencies of the modes were 15% and 40%, and electrical sizes were λ/11.2 and λ/9.5, correspondingly. Finally, we numerically demonstrate the effect of coupling of the two resonators on the operation frequencies.