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Yayın A design technique of 50 Ω terminated bandpass matching network and its implementation to a Y-shaped monopole antenna matching(Springer, 2016-12) Aydın, Çağatay; Atilla, Doğu Çağdaş; Köprü, Ramazan; Kılınç, Sedat; Karakuş, Cahit; Yarman, Bekir Sıddık BinboğaIn this paper, a 50 Ω terminated or in other words transformerless bandpass matching network design methodology and an implementation example are presented. The real frequency techniques are powerful numerical methods to design wideband lossless two-port networks such as filters, matching networks and amplifiers. In these techniques, the value of the termination resistance of the designed network could not be yielded as 50 Ω by numerical package. Hence, a transformer is also required for 50 Ω termination which is not practical for high frequency applications. By employing the proposed procedure, it is guaranteed to obtain transformerless bandpass matching network. Also in this study a wideband suspended monopole antenna is examined. The proposed antenna consists of two major elements; Y-shaped impedance matching plate and hemi-circular radiator. Moreover Y-shaped impedance matching plate connected to a feeding probe excites the suspended hemi-circular radiator via air gap. Consequently, a transformerless bandpass matching network is designed to filter and expand the operational frequency bandwidth of the proposed antenna. It has been observed that ideal circuit and the layout of the matching network simulation have good agreement.Yayın Adaptive Kalman receiver for OFDM systems with transmit diversity in mobile wireless channels(Walter De Gruyter GMBH, 2004-12) Şen, Adnan; Çırpan, Hakan Ali; Panayırcı, ErdalA new joint channel tracking and symbol detection scheme is proposed in this paper for pilot symbol assisted transmit diversity OFDM systems by exploiting the correlation of the adjacent subchannels. Modelling the channel frequency response of every subcarrier corresponding to each transmit antenna as random processes, we employ Kalman filters for both channel tracking and subsequent decoding with diversity gain. Among different stochastic models, the AR model is adopted herein for channel dynamics. Since the proposed adaptive receiver uses two Kalman filters to track the variations of the channel and subsequently to detect the information symbols, they are combined in the coupled receiver structure. Finally the performance of the proposed method is studied through experimental results.
