N-Port Network Theory Applied to Composite Horn/Driver Systems

date October 31, 1985
comments no comments.

Thursday, October 31, 1985 3:30 p.m.

James McLean
Department of Electrical Engineering
The University of Texas at Austin

In recent years, the thrust in acoustic horn loudspeaker design has shifted from impedance matching and power transfer to radiation pattern control. Although the two criteria are not completely incompatible with one another, horn designs which satisfy both are complex and have yet to be perfected. The major difficulty in designing such horns is the lack of a method by which composite acoustic waveguides may be analyzed. Fortunately, the two-port theory underlying microwave waveguide system design is fairly well developed. This theory allows approximate analysis of wave­guide discontinuities and tapers in composite microwave waveguide systems. In recent years, this theory has been extended to an N-port analysis using coupled transmission lines which allows accurate analysis of systems in which mode conversion occurs and multiple propagating modes exist. We are in the process of borrowing this theory almost intact from an obscure book pub­lished in West Germany so that hopefully everyone will think we thought of it ourselves.

Although, the N-port theory has yet to be implemented, the two-port theory has yielded some interesting predictions which are in disagreement with those published in several well-known books. We plan to present experimental data which will hopefully justify our predictions.