Overview: SAS (Serial Attached SCSI), also known as Serial Attached SCSI, is a new generation of SCSI technology, like the current popular Serial ATA (SATA) hard drives, uses serial technology to achieve higher transmission speeds and improves internal space by shortening connection lines. For raw wires, mainly distinguished based on electrical performance, divided into 6G and 12G, and SAS4.0 24G. However, the mainstream production process is still basically the same. For SAS high-frequency lines, impedance, attenuation, loop loss, and crosstalk are the most important transmission indicators. The operating frequency of SAS high-frequency lines is generally above 2.5GHz. High frequency and low loss communication cables are generally made of foam-polyethylene or foam-polypropylene as insulation materials. Two insulated core wires and two ground wires enter the wrapping machine, and aluminum foil and adhesive polyester tape are wrapped around the insulated core wires and ground wires, insulation process design and process control, structure, electrical performance requirements, and transmission theory of high-speed transmission lines.