Manufacturing methods and technology for microwave stripline circuits

This is the final report for work performed on the MANTECH Microwave Stripline Circuit program for the period from 15 January 1981 to 26 February 1982. An investigation was made of the effect of tolerances on a broadband, three-layer, stripline circuit. Tolerances on the following parameters were considered: the dielectric constant of the stripline material, thicknesses of the materials, circuit line widths, alignment of circuits and the surface roughness of the copper cladding. The investigation used both analyses and measurements of actual stripline circuits. An investigation was also made of methods of measuring dielectric constant of the stripline material. The results of the study indicate that a printed wiring board facility can fabricate microwave stripline components if there is good control of all processes. This requires precision measurements of resist photospeed to compensate for lot variations, a highly uniform intensity output of exposure units and also feed and bleed chemical add systems to maintain bath chemistry. Alignment of phototools and machining of the circuit boards is compatible with the CAD/CAM facility and numerically controlled machine tools.