Fundamental interconnect systems for connecting high-speed electronics elements are provided. The interconnect systems consists of signal line, dielectric system with open trench or slot filled up with air or lower dielectric loss material, and the ground plane. The signal line could be for example, microstripline, strip line, coplanar line, single line or differential pairs. The interconnect system can be used for on-chip interconnects or can also be used for off-chip interconnects. The fundamental techniques provided in this invention can also be used for high-speed connectors and high-speed cables.