Post-manufacturing effects of laser ablation process on ceramic-polymer composite substrates

Ceramic-polymer composite substrates are good choice for realization of microwave and millimeter-wave circuits in terms of cost vis-a´-vis performance. Unlike conventional photolithography printed circuits manufacturing, laser structuring offers the fastest, highly repeatable and most accurate manufacturing solution. In this work, the possibility of rapid prototyping of microwave and millimeter wave (MMW) circuits on low-cost ceramic-polymer composite substrates employing laser ablation process is investigated. The measured results indicate that the effective complex permittivity characteristics of the substrate are altered as a consequence of post laser ablation process effect. The effective permittivity alteration phenomenon is validated through the characterization and comparision of various laser ablated and chemically etched Ka band parallel-coupled band-pass filters followed by the permittivity analysis. A simple and experimentally verified method is proposed to utalize the laser ablation structuring process on the prescribed substrate. The method can be used for other substrates as well.