An accurate junction circulator design procedure

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Virginia Polytechnic Institute and State University

A novel circulator design method is presented. It utilizes H. Bosma’s suggested electrical model, a program written for a digital computer representing this model, Fay & Comstock’s design method to calculate electrical and physical properties of applied ferrite cylindrical resonators and measured impedance values of those, for computation of designed circulator performance. The main results are summarized as follows: (i) The method described eliminates the use of the trial and error method in the laboratory. (ii) It permits the prediction of performance accurate within a few dB-s in the 20-30 dB range.

Earlier design methods and proposed solutions are each illustrated by a numerical example. (i) Fay & Comstock’s method (ii) H. Bosma’s method (iii) Proposed solution

The first example exhibits considerable discrepancy between specifications and measured performance of the realized circulator.

The second method is an analysis. Here again predicted performance is quite different from measured performance on the realized device, the parameters of which were used as data for the analysis.

The third method shows good agreement of measured performance and specifications.

Further research possibilities include a refinement of H. Bosma’s boundary value solution and the establishment of an electrical model exhibiting measured puck impedance values for easy matching network synthesis.