Synthesis Techniques for Gain-Bandwidth Optimization in Passive Transducers

This paper is concerned with an approximating technique for realizing the design of broad-band equalizers and matching networks which approach optimum gain bandwidth performance. Given an arbitrary load impedance, it is possible, by methods of Bode, Fano, LaRosa and Carlin, to derive the limiting constraints for optimum flat power or voltage transfer over a prescribed band. The synthesis of equalizer networks to approximate this optimum response is a difficult matter, particularly when the load has some degree of complexity. This is because methods proposed up till now prescribe an approximating transfer function which includes the load characteristics, and the problem of adjusting the parameters of such an approximating function is quite formidable. The technique proposed here bypasses this problem by producing from the idealized gain-bandwidth constraints a set of functions which specifies the equalizer alone. All load dependence is removed from the specifications as an initial step in the synthesis. The final transducer is then synthesized from the approximating functions which are obtained. Examples of one-port and two-port equalizer network designs utilizing this technique will be given.