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New aspects of electromagnetic information theory for wireless and antenna systems
 IEEE Trans. Antennas Propag
, 2008
"... Abstract—This paper investigates informationtheoretic characterization, via Shannon’s information capacity and number of degrees of freedom, of wave radiation (antenna) and wireless propagation systems. Specifically, the paper derives, from the fundamental physical point of view of Maxwell’s equati ..."
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Abstract—This paper investigates informationtheoretic characterization, via Shannon’s information capacity and number of degrees of freedom, of wave radiation (antenna) and wireless propagation systems. Specifically, the paper derives, from the fundamental physical point of view of Maxwell’s equations describing electromagnetic fields, the Shannon information capacity of spacetime wireless channels formed by electromagnetic sources and receivers in a known background medium. The theory is developed first for the case of sources working at a fixed frequency (timeharmonic case) and is expanded later to the more general case of temporally bandlimited systems (timedomain fields). In the bandlimited case we consider separately the two cases of timelimited and essentially bandlimited systems and of purely bandlimited systems. The developments take into account the physical radiated power constraint in addition to a constraint in the source L 2 norm which acts to avoid antenna superdirectivity. Based on such radiated power and current L 2 norm constraints we derive the Shannon information capacity of canonical wireless and antenna systems in free space, for a given additive Gaussian noise level, as well as an associated number of degrees of freedom resulting from such capacity calculations. The derived results also illustrate, from a new informationtheoretic point of view, the transition from near to far fields. Index Terms—Antenna, degrees of freedom, electromagnetic information, information capacity, wave information, wireless. I.
Information Theoretic Optimal Broadband Matching for Communication Systems
"... Abstract—We present an information theoretic perspective on optimal broadband matching. Most of the broadband matching and communication theory literature assumes a frequencyflat reflection coefficient. We derive the optimal capacity and matching network characteristic for a broadband system from an ..."
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Abstract—We present an information theoretic perspective on optimal broadband matching. Most of the broadband matching and communication theory literature assumes a frequencyflat reflection coefficient. We derive the optimal capacity and matching network characteristic for a broadband system from an information theoretic view point while incorporating the broadband matching limitations. We also propose an iterative algorithm to arrive at the optimal solution. We illustrate by an example that a white characteristic for a matching network is often suboptimal for a system with a nonwhite transfer function. I.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1 New Aspects of Electromagnetic Information Theory for Wireless and Antenna Systems
"... This paper investigates certain fundamental aspects not fully covered by previous work on informationtheoretic characterization, via Shannon’s information capacity and number of degrees of freedom, of wave radiation (antenna) and wireless propagation systems. Specifically, the paper derives, from t ..."
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This paper investigates certain fundamental aspects not fully covered by previous work on informationtheoretic characterization, via Shannon’s information capacity and number of degrees of freedom, of wave radiation (antenna) and wireless propagation systems. Specifically, the paper derives, from the fundamental physical point of view of Maxwell’s equations describing electromagnetic fields, the Shannon information capacity of spacetime wireless channels formed by electromagnetic sources and receivers in a known background medium. The theory is developed for both the case of sources working at a fixed frequency (timeharmonic case) and for the more general situation of temporally bandlimited systems. In the bandlimited case we consider separately the two cases of essentially bandlimited and timelimited systems and of purely bandlimited systems. The developments take into account the physical radiated power constraint in addition to the more usual constraint in the source L 2 norm. Based on such radiated power and/or current L 2 norm constraints we derive the Shannon information capacity of canonical wireless and antenna systems in free space, for a given additive Gaussian noise level, as well as an associated number of degrees of freedom resulting from such capacity calculations. This approach constitutes a rigorous, informationtheoretic method to define under given noise the dimensionality of the field. The derived results illustrate, from a new informationtheoretic point of view, the transition from near to far fields. The paper also examines how some of the capacity results for a known background also apply under certain conditions to more general propagation environments having additional multipathing scatterers.