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Although lossy matching is not a standard antenna matching technique, well-designed losses can facilitate wide-band matching of otherwise unmatchable antennas. The lossy matching designs developed in this paper are based on the Pareto front. These Pareto front computations permit the circuit designer to graphically select optimal gain-reflection tradeoffs for lossy matching, readily incorporate other lossless matching bounds, and provide a general approach to difficult wide-band matching problems. Index Terms--Compact antenna, impedance matching, multiobjective optimization, Pareto front.

This paper presents the first implementation of Helton's [H.sup.[infinity]] approach to wide-band impedance matching. The prototypical problem is to maximize the transducer power gain uniformly over an operating band for a load connected to a generator by a lossless two-port. The [H.sup.[infinity]] approach computes the maximum transducer power gain attainable by any lossless two-port uniformly over the operating band. This maximum gain is computed for Fano's classic RLC circuit and an high-frequency antenna represented by measured reflectance data. Index Terms--Fano bounds, gain equalization, Hankel matrices, [H.sup.[infinity]], high-frequency (HF) antennas, impedance matching, lossless circuits.

We present an approximate analysis approach to the computation of probability of error and mean burst error length for a decision feedback equalizer (DFE) that takes into account feedback of decision errors. The method uses a reduced-state Markov model of the feedback process and is applicable to linear modulation formats. We use this technique to analyze a DFE design that mitigates the effects of feedback error by incorporating a soft decision device into the feedback path and a norm constraint on the feedback filter weights. We apply the DFE design and analysis approach to a dispersive multipath propagation environment. Index Terms--Decision feedback equalizers, error analysis, error propagation, Markov processes.