Computer Aided Design for TE01 Mode Circular Waveguide
Prior work cannot be directly extrapolated to compact, optimized bends, structures with less overmoding, and limited dielectric material selection for high power application in radar and radio communications. Accordingly, the need exists for practical circular overmoded waveguide of optimum design and for some mechanism to facilitate the determination of appropriate design for diverse practical applications, in order to accurately predict performance given selected design and material input parameter values.
The present invention relates generally to circular overmoded waveguide and, in particular, to circular overmoded waveguide of the dielectric lined and sheathed helix types which are optimally designed, utilizing a novel computerized design procedure to characterize and predict operational performance, given design and material input parameter values. The computer software proposed in accordance with the present invention improves upon the prior art noted above in that it enables higher performance waveguide design with higher predicted fidelity and increased region of validity.
Input design parameters including: a) for lined waveguide; operating frequency, waveguide radius, dielectric lining thickness, and lining complex permitivity; and b) for helix waveguide; frequency, helix radius, sheath thickness, helix wire diameter, helix insulation and pitch, and sheath complex permitivity.
Default values for waveguide diameter and bend curvature profile and bend length based on frequency and on design and experimental experience.
Bend optimization for minimum loss with both constrained and unconstrained bend length.
Diagnostics to indicate if any assumption or approximation validity is exceeded.
Warning if input values or resultant waveguide performance calculations indicate a potentially inoperable design.
Calculation of waveguide run loss based on run length and selected number of bends.
The foregoing features combine to render the design software of the present invention quite versatile and of substantial utility in the design of optimized circular overmoded waveguide for practical application. For example, by means of the proposed software, a significant number of design parameter value combinations in both the upper (X) and lower (S) microwave bands have been investigated, as well as a variety of practical materials, and based thereon, optimal overmoded waveguide structural design for straight and bend sections has been determined.
The computer software has been validated both numerically and experimentally. Numerical validation consisted of comparison of interim results with published results in the original, higher millimeter band telecommunications designs featured in the references. By way of experimental validation, designs determined using the novel software of the present invention have been reduced to practice, at S and X bands, and experimental performance results are in good agreement with the computer predictions.
In accordance with the foregoing discussion, a principal object of the present invention is to facilitate the design of low loss, high power overmoded waveguide specifically for S and X band operation and more generally for the microwave and lower millimeter wave bands.
Another object of the invention is to provide a circular overmoded TE.sub.0l waveguide of optimal design for either the dielectric lined or sheathed helix waveguide configuration or a combination thereof.
A still further object of the invention is to permit the computer aided design of circular overmoded waveguide of practical application.