In this paper, an alternative approach is presented, to design equalizers (or matching networks) with commensurate (or equal length) transmission lines. The new method automatically yields the matching network topology with characteristic impedances of the commensurate lines. In the implementation process of the new technique first, the driving point impedance data of the matching network is generated by tracing a pre-selected transducer power gain shape, without optimization. Then, it is modelled as a realizable bounded-real input reflection coefficient in Richard domain, which in turn yields the desired equalizer topology with line characteristic impedances. This process results in an excellent initial design for the commercially available computer aided design (CAD) packages to generate final circuit layout for fabrication. An example is given to illustrate the utilization of the new method. It is expected that the proposed design technique is employed as a front-end, to commercially available computer aided design (CAD) packages which generate the actual equalizer circuit layout with physical dimensions for mass production.

The electrical characteristics of biologically active points (BAPs) compared with those of the surrounding human skins are investigated. We confirm that BAPs have lower resistance and higher capacitance than the surrounding skins have. We find that BAPs have higher characteristic frequency than surrounding skins and sometimes the impedance spectra of BAPs have two semicircles on the complex impedance plane. Therefore, we propose the skin impedance model that is proper to the BAPs. This model describes our experimental results sufficiently.