Low-Loss Flex Circuit Interconnect: Development of Reduced Insertion-Loss Flexible Packaging

Developing trends within the Industrial, Consumer Electronics and Aerospace & Defense arenas have increased the demand for high-speed, high-density flexible printed circuit solutions. The goal of this paper is to describe the loss contributors within conventional flexible printed circuit constructs and how their content can be reduced to improve insertion loss and reduce attenuation. Reduction (or eventual removal) of conventional bonding film adhesive and potential future changes to existing dielectric and/or adhesive materials are considered to reach desired performance targets. Based on simulation results and laboratory measurements, this paper will describe significant loss improvements to conventional flex cross sections and outline plans for future improvements. Moreover, we will describe why this research may be of value to the signal integrity (SI) engineer working within a cost-sensitive and performance oriented application. Finally, we will discuss what new applications are enabled through the reduction of lossy conventional flexible circuit cross-sections cannot provide loss characteristics required by high-speed applications with interconnect distances of more than a few inches. Therefore, more costly bundled solutions, such as "ribbonized" coax or fiber optics are commonly employed to meet electrical requirements of high-speed applications requiring mechanical flexibility. The goal of this paper is to describe the loss contributors within conventional flexible printed circuit constructs and how their content can be reduced to improve insertion loss and reduce attenuation. Reduction (or eventual removal) of conventional bonding film adhesive and potential future changes to existing dielectric and/or adhesive materials are considered to reach desired performance targets. Based on simulation results and laboratory measurements, this paper will describe significant loss improvements to conventional flex cross sections and outline plans for future impro- vements. Moreover, we will describe why this research may be of value to the Signal Integrity (SI) engineer working within a cost-sensitive and performance oriented application. Finally, we will discuss what new applications are enabled through the reduction of lossy conventional flexible circuit cross-section dielectric materials.