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In this paper, we first present a novel synthesis method based on an even-and odd-mode decomposition. This method is capable of synthesizing a network under very general hypotheses and is, therefore, suitable for lossy filter design. To exploit the increased flexibility of this new synthesis method over the traditional lossy design techniques, we then introduce a new approach to the design of lossy filters based on the characteristic polynomials evaluation. This new technique can offer many advantages over traditional techniques, and the main one is that, once the transmission function of the filter is known using traditional methods, the reflection function can be constrained with a certain degree of freedom. A tradeoff between additional constraints and redundancy in the final network must be accepted. Finally, we present design examples and a practical realization, which validate this novel approach to the design of lossy filters.Index Terms-Lossy filters, microwave filter synthesis, polynomial filter synthesis.

The 2 nd -generation satellite digital video broadcasting (DVB-S2) system is at present under review with the aim of improving its spectral efficiency. In this paper, we have addressed the problem to optimize the user bandwidth taking into account a realistic satellite broadcasting channel. Two different receiver architectures have been evaluated in order to maximize the system spectral efficiency. Finally, some considerations on the OMUX dissipated power have been reported. Nomenclature α = Shaping pulse roll-off AWGN = Additive white Gaussian noise f T = Transponder bandwidth (or frequency spacing among adjacent channels) FTN = Faster-than-Nyquist ICI = Inter-channel interference IMUX = Input multiplexer ISI = Inter-symbol interference LMS = Least mean square MMSE = Minimum mean square error N u = Number of transmitting users OMUX = Output multiplexer SE = Spectral efficiency P sat = On-board saturation power R s = Symbol rate T s = Symbol interval TF = Time-frequency 1 Communication System Engineer, TEC-ETC, stefano.cioni@esa.int . 2 Microwave Engineer, TIA-TTP, christoph.ernst@esa.int . 3 Head of Communications and TT&C Section, TEC-ETC, alberto.ginesi@esa.int . 4 Associate Professor, SPADiCLab, giulio@unipr.it . Downloaded by CARLETON UNIVERSITY LIBRARY on July 30, 2015 | http://arc.aiaa.org |

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